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The International Conference on New Frontiers in Physics aims to promote scientific exchange and the development of novel ideas in science with a particular accent in interdisciplinarity. The conference will bring together worldwide experts and promising young scientists working on experimental and theoretical aspects of particle, nuclear, heavy ion and astro-particle physics and cosmology, with colleagues from other disciplines, for example, solid-state physics, mathematics, mathematical physics, quantum optics and other.
The conference will be hosted in the Conference Center of the Orthodox Academy of Crete (OAC), an exceptionally beautiful location only a few meters from the Mediterranean sea.
In the past few decades particle physics has made giant leaps by studying matter at the shortest distance scales with detectors built on a few paradigms (track-first-destroy-later, redundancy, cross-verification and calibration) which worked very well, but which today look increasingly misaligned with the progress of information-extraction procedures. In addition, our technology nowadays allows for non-planar geometries and solutions that may significantly boost the performance of those devices. However, the construction choices live in a hundreds-dimensional parameter space which humans cannot probe. The result is a huge potential loss in performance.
Our saviour may be differentiable programming, which allows to create precise models of detectors, pattern recognition and inference extraction, cost, other constraints, and detector-related systematic uncertainties, as well as, crucially, a carefully constructed objective function. Backpropagation through a differentiable pipeline of all the elements of the problem may allow to probe the design space and realign design and goals of experiments that base their operation on the interaction of radiation with matter, besides finding entirely new ways to solve our detection problems.
In this seminar I will illustrate how we can set out to create the interfaces to solve our difficult optimization problems, with great prospects for future endeavours that allow for time and resources to carry out such studies.
The past decades have witnessed the exciting discovery of more and more hidden-charm states beyond the conventional meson and baryon scheme. The LHCb experiment at the LHC has been at the forefront of this endeavour given its large heavy hadron yield and unique capability in reconstructing heavy hadrons. This talk presents a selected results of the recent experimental progress on exotic hadrons from LHCb.
Recent astronomical observations present a surprising indication to existence of antimatter stars in the Galaxy. A model which predicted a significant population of galactic anti-stars is described. Observational bounds on anti-star density in the Galaxy are reviewed. A new observational signature of anti-stars is discussed.
Cosmological energy density of dark matter (DM) particles is
determined by their interaction strength, their mass, and the universe
expansion law. The frozen density of DM particles is determined by the
Zeldovich kinetic equation. In the canonical theory a natural
candidate for dark matter, the lightest supersymmetric particle
(LSP), is practically excluded by the recent lower bound on its mass
obtained at LHC. In this connection it is interesting to consider
modified gravity theories which could lead to significant deviation of the
expansion regime from that in the conventional cosmology. As a
realistic example we discuss $R^2$ inflationary model, suggested by
Starobinsky. We have shown that particle production by oscillating
curvature (scalaron) could significantly diminish the density of
stable relics. Depending on the channel of the scalaron decay the
proper value of the mass of the LSP-type particle, allowing it to make
the cosmological dark matter, can be in the range from $10^6$ GeV up to $10^{12}$ GeV.
The next paradigm change in computing, now underway, is based on artificial intelligence. The so-called deep learning revolution of the late 2000s has significantly changed how scientific data analysis is performed and has brought machine-learning techniques to the forefront of high-energy physics analysis. Such techniques offer advances in areas ranging from event selection to particle identification to event simulation, accelerating progress in the field while offering considerable savings in resources.
This lecture will give a historical introduction of the topic to then cover the latest techniques used in high energy physics
Possible temporal variations of nucleus decay parameters studied extensively in the last years, their observation can be the signal of unknown physical effects. Several experiments reported the annual and daily decay rate oscillations in alpha and beta-decays of some radioactive nuclides oat the level of .05 % [1,2]. Also, correlation of Mn-54 e-capture decay rate with electromagnetic solar activity was reported [1]. BSTU - PhIAN collaboration studies decay rate variations in inverse beta-decay (e-capture) of Fe-55 isotope. In this process K-shell electron absorbed by nuclei and electron neutrino emitted; it accompanied by X-ray with energy 5,9 or 6,4 KeV which in our set-up detected by cooled Si-Pin detectors. Measurements of decay rate performed in 2016 -2020 , demonstrate that together with observed Fe-55 decay exponent with life-time 1004 days, oscillation period 29.5 +/- 1.5 days corresponding to moon month is found with amplitude (.22 +/- .04)% ;
possible model of such deviations considered in [3].
Possible influence of electromagnetic solar activity was studied during 2015 – 2020 for Fe-55 decay rate, simultaneously with Co-60 beta-decay rate measured by germanium detector in Novosibirsk INF at the distance 2800 km from Moscow [4]. The deviations of similar form and size from exponential decay low at the average level (.55 +/-.004)% were detected in both experiments during October- December 2018. Supposedly, they can be related to solar activity minimum started in the beginning of 2019. In addition, six decay rate dips of the order 1 % of decay rate and with duration from 40 to 208 hours were found. It is shown that their occurrence correlate with x-ray solar flare events with significant reliability, existence of such correlation can have important practical applications [4]. SOLARIS project of our collaboration plans to perform simultaneous measurements of Fe-55, Co-60 decay parameters on International Space Station and Earth and
studies of their correlation with electromagnetic solar activity.
1. E. Fischbach et al. , Rev. Space Sci. 145, 285 (2009); Astrop. Phys. 59,47 (2014)
2. E. Alekseev et al. , Phys. Part. Nucl. 47, 1803 (2016); ibid. 49, 557 (2018)
3. S. Mayburov Int. J. Theor. Phys. 60, 630 (2021)
4. S. Bogachev et al. J. Phys.: Conf. Series 1690, 012028-012035 (2020)
The LHCb detector at the LHC specialises in studying decays of beauty and charm hadrons, with excellent tracking, secondary vertex reconstruction and particle identification capabilities. Here we present an overview of recent highlighted results from the broad physics programme at LHCb, including the flavour anomalies and precise determination of CKM parameters. The detector is currently undergoing a large upgrade, the extent and physics potential of which will briefly be discussed.
A review of recent ATLAS physics results will be given.
TBA
The ALICE experiment at the LHC plays a key role in the studies of the hot and dense QCD medium, the quark-gluon plasma, which can be recreated in ultrarelativistic heavy-ion collisions. Furthermore, ALICE has provided signi?ficant contributions to the investigation of a possible formation of such a medium in small collision systems, to the characterisation of the energy evolution of the gluon content of di?erent targets by means of ultra-peripheral collisions, and other areas.
In this presentation, we will highlight recent ALICE results that provide an important step towards our understanding of the QCD matter explored with pp, p|Pb, Xe|Xe and Pb|Pb collisions at the LHC. As we are approaching the end of the Long Shutdown 2 at the LHC, we will also present updates of the ALICE detector in view of the upcoming Run 3 and beyond.
The High Luminosity Large Hadron Collider (HL-LHC) will deliver to the CMS experiment a design integrated luminosity of 3000 $fb^{-1}$, across its ten years long operations. This unprecedented amount of data will allow for precise measurements of the Standard Model and will extend the reach of new physics searches. The higher instantaneous luminosity will result in a larger number of collisions per bunch crossing (pileup) and a higher radiation fluence, particularly in the innermost regions of the detector and in the endcaps. The phase-2 upgrade project of CMS, conceived to address these challenges, will be presented in this talk.
The ALICE Collaboration completed the upgrade of the detector for the LHC Run 3 and is now commissioning for upcoming first collisions in LHC pilot runs for data taking. In parallel, R&D activities and simulation studies are being performed to define the future of the experiment beyond LHC Run 3.
Two detector upgrades are foreseen for the next long shutdown (LS3). The first is the replacement of the three beam-pipe closer layers of the Inner Tracking System with a novel vertex detector consisting of curved wafer-scale ultra-thin silicon sensors arranged in perfectly cylindrical layers to improve impact parameter resolution and significantly extend the physics capability for the study of heavy-flavour production and low-mass dielectrons. The second upgrade for the LS3 is the addition of a novel concept Forward Calorimeter (FoCal) detector at large rapidity consisting of a Si-W electromagnetic calorimeter with pad and pixel readout, that will equip the experiment with unique capabilities to measure small-x gluon distributions via prompt photon production.
A proposal of a next-generation heavy-ion experiment for LHC Run 5 is also in preparation and will be discussed. The aim is to perform novel measurements of electromagnetic and hadronic probes of the QGP, such as the production of multiply-charmed baryons, which have so far been inaccessible, both because of detector performance and luminosity. The concept of the new apparatus foresees an extensive usage of thin silicon sensors for tracking and a modern particle identification system, combining a silicon-based time of flight detector, a RICH and preshower detector.
After the observation of a Higgs boson in 2021, the cms collaboration started to study its properties and couplings. In this talk I will review recent work by the CMS Collaboration, spanning all active areas of the CMS Higgs Physics Program
The latest results on the production of Higgs boson pairs (HH) in the ATLAS experiment are reported, with emphasis on searches based on the full LHC Run 2 dataset at 13 TeV. In the case of non-resonant HH searches, results are interpreted both in terms of sensitivity to the Standard Model and as limits on kappa_lambda, i.e. a modifier of the Higgs boson self-coupling strength. Searches for new resonances decaying into pairs of Higgs bosons are also reported. Prospects of testing the Higgs boson self-coupling at the High Luminosity LHC (HL-LHC) will also be presented.
We present various recent jet and vector boson + jet precision measurements at 5 and 13 TeV performed with data recorded between 2015 and 2018, including processes whose production rates cover several orders of magnitude. We compare unfolded measurement to the latest fixed-order and event generator calculations, use jet data to extract PDFs and SM parameters, and investigate possible 4-quark contact interactions as well as double-parton scattering.
The LHCb experiment offers a phase space which is complementary with respect to ATLAS and CMS.
Thanks to its forward acceptance and its precise vertex reconstruction, studying electroweak physics at LHCb can provide precise measurements of Standard Model parameters, like the W boson mass, and unique constraints to Parton Distribution Functions.
In this presentation the latest measurements on $W$ and $Z$ bosons production performed during LHCb Run II data taking are presented.
Finally, future prospects for electroweak physics at LHCb and its future upgrades are also presented.
The discovery of the Higgs boson with the mass of about 125 GeV completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many measurements, it is not capable to solely explain some observations. Many extensions of the Standard Model addressing such shortcomings introduce additional Higgs-like bosons which can be either neutral, singly-charged or even doubly-charged. The current status of searches based on the full LHC Run 2 dataset of the ATLAS experiment at 13 TeV are presented.
With the full Run 2 pp collision dataset collected at 13 TeV, very detailed measurements of Higgs boson properties can be performed using its decays into bosons. This talk presents measurements of Higgs boson properties using decays into bosons and their combination with fermionic decays, including production mode cross sections and simplified template cross sections, as well as their interpretations.
Testing the Yukawa couplings of the Higgs boson to quarks and leptons is important to understand the origin of fermion masses. The talk presents several new measurements in Higgs boson decays to two bottom quarks or two tau leptons, searches for Higgs boson decays to two charm quarks or two muons, as well as indirect constraints of the charm-Yukawa coupling. The production of Higgs bosons in association with top quarks will also be discussed. These analyses are based on pp collision data collected at 13 TeV.
Ruben Muradyan (piano), Svetlana Nor (violin), Vladimir Nor (cello)
Gamma-Ray Bursts constitute one of the most fascinating and relevant phenomena in modern science, with strong implications for several fields of astrophysics, cosmology and fundamental physics. In this review, I will focus on the perspective key-role of GRBs for cosmology and multi-messenger astrophysics. Indeed, the huge luminosity, the redshift distribution extending at least up to z$\sim$10 and the association with the explosive death of very massive stars make long GRBs (i.e., those lasting up to a few minutes) potentially extremely powerful probes for investigating the early Universe (pop-III stars, cosmic re-ionization, SFR and metallicity evolution up to the "cosmic dawn") and cosmological parameters. At the same time, as demonstrated by the GW170817 event, short GRBs (lasting no more than a few s) are the most prominent electromagnetic counterpart of gravitational-wave sources like NS-NS and NS-BH merging events. Moreover, both long and short GRBs are expected to be associated with neutrino emission. I will also report on the status, concepts and expected performances of space mission projects aiming at fully exploiting these unique potentialities of the GRB phenomenon, thus providing an ideal sinergy with the large e.m. facilities of the future like LSST, ELT, TMT, SKA, CTA, ATHENA in the e.m. domain, advanced second generation (2G++) and third generation (3G) GW detectors and future large meutirno detectors (e.g., Km3NET).
Third Observation (O3) run of Advanced LIGO and Advanced Virgo started in April 2019 and ended in March 2020; reaching sensitivities significantly better than those in the previous observing run. This talk will overview the published science results achieved during the O3 run, focusing on the catalog of the gravitational waves signals due to compact binary coalescences (GWTC-2) and on the main outcomes of follow-up investigations, e.g. tests of general relativity. Among gravitational waves signals reported in GWTC-2, a few have been associated to exceptional scientific case such as binary system with significantly asymmetric mass ratios (GW190412), intermediate-mass black holes (GW190521), neutron stars-black holes binary system (GW200105 and GW200115), these will be discussed.
In addition results from searches of gravitational waves due to other astrophysical sources including transient bursts, continuous waves, and stochastic background in O3 data will be reported.
Recently, efforts on the building of Hf-based crystal scintillators
have been performed. The technique allows the implementation of the
so-called “source = detector” approach to study rare nuclear processes
in Hf isotopes with higher efficiency with respect to the HP-Ge
spectrometry. In this talk, a review of recent studies concerning rare
nuclear processes in Hf isotopes will be addressed.
Preliminary studies on double beta decay processes in $^{106}$Cd were performed by using a cadmium tungstate scintillator $^{106}$CdWO$_4$ (mass 215.4 g) enriched in $^{106}$Cd at 66%, together with two natural CdWO$_4$ scintillation detectors. Their geometry was such to cover a large part of the solid angle around the enriched crystal. The experiment is enclosed in the DAMA/R&D setup, located at the LNGS. Monte Carlo simulations were carried out in order to study the background and the contaminations present in the various materials of the experimental set-up and the expected signal. New half-life limits have been set on the various double beta decay channels of $^{106}$Cd at the level of lim T$_{1/2}$$\sim$10$^{20}$-10$^{22}$ yr. They were obtained through the analysis of data accumulated for 467 days, studying the coincidence and/or anticoincidence events in the three detectors. The sensitivity obtained on the T$_{1/2}$ for the positron-emitting electron capture process with two neutrinos emission in $^{106}$Cd was preliminarily estimated as T$_{1/2}$ $\ge$ 1.6 $\times$ 10$^{21}$ yr, which is within the region of the theoretical predictions for this process i.e. in the range of T$_{1/2}$ = 10$^{21}$-10$^{22}$ yr.
The half-life of ${}^{212}$Po (one of the ${}^{232}$Th daughters) was measured with the highest up-to-date accuracy using a thorium-loaded liquid scintillator. The scintillator was produced by a solution of thorium and trioctylphosphine oxide complex in toluene in 0.1 % mass concentration of Th (${}^{232}$Th activity in scintillator is 4.61 Bq/mL). 12 mL of the scintillator was optically connected to a fast photomultiplier tube Hamamatsu R13089-100-11 with 2 ns rise time and 0.17 ns transit time spread (FWHM). The scintillation waveforms were recorded by a high frequency oscilloscope LeCroy WavePro 735Zi-A with a sampling frequency of 20 GS/s and 3.5 GHz bandwidth. In total about 50 millions of events were recorded and about 2.7 millions of BiPo-pairs were selected by using the digital constant-fraction discrimination technique. A rather high signal to background ratio on the level of 0.3 $\times$ $10^6$ was achieved in the time interval 80 – 1600 ns. The obtained half-life of ${}^{212}$Po is $T_{1/2}$ = (295.1 $\pm$ 0.4) ns which is the most accurate up-to-date (relative uncertainty: 0.14 %). The value is in agreement with the recommended one T1/2 = (294.3 $\pm$ 0.8) ns [1] and with the recent experimental results obtained with a liquid scintillator [2] and a xenon liquid/gas time projection chamber [3].
[1] K. Auranen, E.A. McCutchan, Nuclear Data Sheets for A = 212, Nucl. Data Sheets 168 (2020) 117.
[2] G. Bellini et al., Lifetime measurements of 214Po and 212Po with the CTF liquid scintillator detector at LNGS, Eur. Phys. J. A 49 (2013) 92.
[3] E. Aprile et al., Results from a calibration of XENON100 using a source of dissolved radon-220, Phys. Rev. D 95 (2017) 072008.
The Cryogenic Underground Observatory for Rare Events (CUORE) is the first bolometric experiment searching for 0νββ decay that has been able to reach the one-tonne mass scale. The detector, located at the LNGS in Italy, consists of an array of 988 TeO2 crystals arranged in a compact cylindrical structure of 19 towers. CUORE began its first physics data run in 2017 at a base temperature of about 10 mK and in April 2021 released its 3rd result of the search for 0νββ, corresponding to a tonne-year of TeO2 exposure. This is the largest amount of data ever acquired with a solid state detector and the most sensitive measurement of 0νββ decay in 130Te ever conducted, with a median exclusion sensitivity of 2.8×10^25 yr. We find no evidence of 0νββ decay and set a lower bound of 2.2 ×10^25 yr at a 90% credibility interval on the 130Te half-life for this process. In this talk, we present the current status of CUORE search for 0νββ with the updated statistics of one tonne-yr. We finally give an update of the CUORE background model and the measurement of the 130Te 2νββ decay half-life, study performed using an exposure of 300.7 kg⋅yr.
The high precision X-ray spectroscopy of exotic atoms, in particular of kaonic atoms, offers the unique opportunity to investigate the strong interaction (QCD) in the low-energy regime, by allowing to directly access the antikaon-nucleus interaction at threshold. In order to do this, a new dedicated technology of Silicon Drift Detectors (SDDs) has been developed by the SIDDHARTA-2 collaboration, with an optimized geometry for the detectors, with a new field configuration and read-out electronics, which allow the SDDs to work in the high and variable background environment of a collider. The unique characteristics of the SDDs make them ideal for kaonic atoms experiments such as SIDDHARTA-2 at LNF-INFN and E62 at J-PARC. These detectors are also used in testing the Pauli Exclusion Principle in the VIP experiment at the underground LNGS.
This contribution will present the characterization and optimization of the SDDs and the first results coming from their use in measurement of kaonic helium during the 2021 the DAFNE collider commissioning phase, in preparation for the SIDDHARTA-2 kaonic deuterium run. Future plans for the development of 1 mm-thick Silicon Drift Detectors for exotic atoms spectroscopy in higher energy domain will be discussed.
I will discuss a novel scenario of Dark Matter production naturally connected with generation of gravitational waves. Dark Matter is modelled as a real scalar, which interacts with the hot primordial plasma through a portal coupling to another scalar field. For a particular sign of the coupling, this system exhibits an inverse second order phase transition. The latter leads to an abundant Dark Matter production, even if the portal interaction is so weak that the freeze-in mechanism is inefficient. The model predicts domain wall formation in the Universe, long time before the inverse phase transition. These domain walls have a tension decreasing with time, and completely disappear at the inverse phase transition, so that the problem of overclosing the Universe is avoided. The domain wall network emits gravitational waves with characteristics defined by those of Dark Matter. In particular, the peak frequency of gravitational waves is determined by the portal coupling constant, and falls in the observable range for currently planned gravitational wave detectors.
CERN Axion Solar Telescope (CAST), an helioscope since 20 years searching for solar axion, has recently evolved into an haloscope exploring the dark matter axion using resonant microwave cavities. CAST-CAPP is a subdetector mounted in the bore of CAST magnet, consisting of 4 individual cavities that can be phase-matched. Phase-matching is a novel technique in the axion community that help increase signal SNR, especially needed when probing higher axion masses to compensate the decreasing cavity volume. In this talk, we will give an account of the latest results where CAST-CAPP improves the existing axion-photon coupling limit by more than an order of magnitude in range of 19.7 – 22.4 μeV axion mass.”
Over the last years, satellite experiments as the Alpha Magnetic Spectrometer on board the International Space Station measure antimatter cosmic ray fluxes, including antiprotons and recently antimatter nuclei. These measurements provide a novel probe to search for new physics including annihilations of dark matter in the Milky Way. I will present an excess of cosmic-ray antiprotons at the GeV range, that could be accounted for by a dark matter particle in the mass range of 50 to 90 GeV. I will also discuss the prospects of detecting anti-deuterons and anti-Helium nuclei produced both from inelastic collisions of high energy cosmic-rays with the interstellar medium gas and from dark matter annihilations. Interestingly, under certain astrophysical assumptions AMS may detect cosmic-ray anti-deuterons and anti-Helium from annihilating dark matter particles.
We examine the effect of anisotropic photon polarisation tensor in the longitudinal electrical conductivity. We consider strongly quantizing domain of neutron star crust for significant thermodynamic contribution for the calculation of transport coefficient. We solve Boltzmann equation in presence of magnetic field to obtain dissipative component of the conductivity tensor. Electrical conductivity is formulated considering anisotropic photon polarisation tensor with magnetically modified screening. The photon polarization tensor in presence of magnetic field is calculated in the weak coupling regime employing hard dense loop approximation. Evaluation of electrical conductivity receives significant modification due to inclusion of anisotropic polarisation tensor in the formalism.
One of the main limitations in particle physics analyses in which the signal selection is based on machine learning is the understanding of the implications of systematic uncertainties. The usual approach consisting in the training with samples ignoring systematic effects and estimating their contribution to the magnitudes measured on modified test samples. We propose here an alternative method based on data augmentation to incorporate the systematics at the training time, which provides both an improvement in the performance and a reduction in the biases.
Many searches at the LHC experiments target topologies with three or more invisible particles in the final state. The reconstruction of the full event kinematics is in general not possible even using the information provided by the missing transverse momentum or by the constraints based on the presence of known-mass resonances in the decay chain process. On the other hand, the space of momentum solutions for the invisible particles is frequently small enough to allow their inference through the momentum correlations of the visible particles. This work proposes an example in which a dark matter mediator is produced in association with one or two top quarks decaying semi-leptonically and yielding two neutrinos plus the mediator in the final state. A neural network has been trained in regression mode to predict the transverse momentum of the dark matter mediator, achieving a resolution of about 30%. These ideas could be exploited at the LHC experiments to characterize and discriminate possible signal events from standard model backgrounds.
In heavy-ion collisions at large particle colliders, such as LHC or RHIC, heavy-flavour (charm and beauty) quarks are produced mainly through initial hard scatterings. Therefore, they can serve as probes of the properties of the hot medium created in such collisions. Hadrons, that contain such quarks, could not be directly detected, thus they are measured via reconstruction of their decay products. However, due to the large number of particles produced in such collisions, separation of the decay products from combinatorial background is challenging and advanced statistical analysis is needed.
In this presentation, we present analysis of $\mathrm{D}^{0} (\overline{\mathrm{D}^{0}})\rightarrow \mathrm{K}^- \pi^+ (\mathrm{K}^+ \pi^-)$ decay to investigate performance of machine learning algorithms in order to find the most effective way how to separate signal from random combinatorial background. For this study, we use HIJING and STAR detector simulation of d+Au collisions at $\sqrt{s_\text{NN}}=200$~GeV embedded to the collisions recorded with the STAR. We compare deep neural network implemented using Keras with TensorFlow backend, random forest model implemented using scikit-learn and boosted decision trees implemented using The Toolkit for Multivariate Data Analysis with ROOT. Described methods might be applied on reconstruction of any two-body decay in high-energy physics experiments.
A challenge for future particle-physics experiments at the high-energy frontier is the precise measurement of muon momenta at very high energy. In this work we discuss the feasibility of an entirely new avenue for the measurement of the energy of muons based on their radiative losses in a dense, finely segmented calorimeter. We demonstrate with an idealised calorimeter layout, how spatial and energy information on emitted electromagnetic radiation may be exploited with 3D convolutional neural networks to obtain an estimate of the muon energy. We show that the fine-grained information on the radiation patterns allows for a significant improvement of the precision of muon energy estimates. Additionally, we show that the regression is entirely complementary to traditional tracker-based measurements, allowing one to achieve good resolution across the energy spectrum.
Searches for pairs of Higgs bosons will be, in all likelihood, the best tools to precisely measure the Higgs boson self-coupling $\lambda_{hhh}$ in future colliders. We study various strategies for the $hh\to b \bar{b} b \bar{b}$ search in the HL-LHC era with focus on constraining $\lambda_{hhh}$. We implement a machine-learning-based approach to separate signal and background and apply recent advances in machine learning interpretability, compare the traditional 4 $b$-jet reconstruction to final states with 1 or 2 large-radius jets, and test scenarios with different top-quark Yukawa couplings, among other factors.
Based on arXiv:2004.04240.
In the coming years the present gravitational wave detectors LIGO, Virgo and KAGRA, will maximize their sensitivity with the aim to reach a detection rate greater than one gravitational event per day. This is foreseen during the fifth observation period O5, starting from 2025.
Moreover, the future generation of ground-based observatories (3G), planned after 2030, the Einstein Telescope (in Europe), the Cosmic Explorer (in the USA) and the Nemo (in Australia), will be able to extend the observation window for gravitational signals and intercept not only the cosmic events produced by the fusion of black holes and neutron stars, but also the gravitational signals generated in the early phases of the life of our Universe.
We will present which are the plans for the interferometers including the ideas foreseen for the post-O5 period till the start of the 3G interferometers data taking.
The NA62 experiment at CERN reports searches for K+ → e+N, K+→μ+N and K+→μ+νX decays,
where N and X are massive invisible particles, using the 2016-2018 data set.
The N particle is assumed to be a heavy neutral lepton, and the results are expressed as upper limits
of O(10−9) and O(10−8) of the neutrino mixing parameter |Ue4|2 and |Uμ4|2, improving on the earlier
searches for heavy neutral lepton production and decays in the kinematically accessible mass range.
The X particle is considered a scalar or vector hidden sector mediator decaying to an invisible final
state, and upper limits of the decay branching fraction for X masses in the range 10-370 MeV/c2 are
reported for the first time, ranging from O(10−5) to O(10−7).
An improved upper limit of 1.0 10−6 is established at 90% CL on the K+→μ+ννν branching
fraction.
In the framework of the Standard Model we present a new theoretical predictions for partial widths, double and single differential distributions for four-leptonic decays of $B_s$ - mesons. We consider the contributions of $φ (1020)$ - resonance, $J/ψ$ - and $ψ(2S)$ - resonances (excluding resonant regions), non-resonance contribution of the $b \bar{b}$ - pairs, leading contribution of “weak annihilation” and bremsstrahlung. We use the model of vector meson dominance for calculation of resonances contributions and take into account a set of new contributions that were not previously considered.
Hypercentral Constituent Quark Model has been exploited to obtain the radial and orbital resonance masses of light baryons. The confining term of the potential is chosen as linear for the present study. The obtained results are compared with the available experimental data as well as other phenomenological and theoretical models, however the strange quark baryons Ξ and Ω are least observed in experiments so far. The calculated results range for all possible spin-parity assignment for S-state to F-state. The magnetic moments have been obtained through effective mass formalism. Also, few decay widths for radiative decay have been observed to be in accordance with the PDG data. The upcoming experimental facilities may provide with new information to analyze the model in all aspects.
Statistical models are widely used for investigation of complex system’s
behaviour. Most of the models considered in the literature are formulated on regular
lattices with nearest neighbour interactions. The models with non-local interaction
kernels have been less studied. In this article we investigate an example of such a
model – non-local q-color Potts model on a random d = 2 lattice. Only the same
color spins at unit distance (within some small margin δ) interact. We study the
vacuum states of this model and present the results of numerical simulations and
discuss qualitative features of the corresponding patterns. Conjectured relation with
the chromatic number of a plane problem is discussed.
The DArk Matter Particle Explorer (DAMPE) is a particle detector hosted on board a satellite orbiting around the Earth since December 2015. The space mission has been promoted by the Chinese Academy of Science and results from an international effort also including italian and swiss institutions. The scientific goals include: indirect detection of Dark Matter signatures in cosmic lepton spectra, study of Cosmic Ray energy spectra up to energies of hundreds of TeV and high-energy gamma ray astronomy. A general overview of the mission will be presented and its main results about the all-electron, proton, helium, light-component (p+He) and heavier nuclei energy spectra, as well as studies on gamma-ray sources, will be discussed.
The High Energy cosmic Radiation Detector (HERD) is one of the prominent space-borne instruments to be installed on board the Chinese Space Station (CSS) in 2027 and is the result of a collaboration among chinese and european institutions. Primary scientific goals of HERD include: precise measurements of the cosmic ray (CR) energy spectra and mass composition at energies up to few PeV, electron/positron spectra up to tens of TeV, CR anisotropy, gamma ray astronomy and transient studies, along with indirect searches for Dark Matter particles. HERD is configured to accept incident particles from both its top and four lateral sides. Owing to its pioneering design, more than one order of magnitude increase in geometric acceptance is foreseen, with respect to previous and ongoing experiments.
In its baseline configuration, HERD is conceived around a deep (~55 X$_0$, 3 λ$_I$) 3D cubic calorimeter (CALO), forming an octagonal prism of approximately 7500 LYSO crystals. Fiber Tracker (FiT) mats are instrumented on all active sides surrounding the calorimeter, in order to accurately determine tracks of impinging particles. Furthermore, a Plastic Scintillator Detector (PSD) is covering the calorimeter and tracker, providing gamma–ray and charged particle triggers, with an additional level of charge measurement. Ultimately, a Silicon Charge Detector (SCD) envelops the above-stated sub-detectors, ensuring an additional determination of the charge. For energy calibration purposes (in the TeV scale), a Transition Radiation Detector (TRD) will be placed on one of the lateral faces. In this work, the latest advancements and scientific objectives of the HERD space mission will be presented along with a detailed overview of ongoing and upcoming activities.
One of the big problems of modern cosmology is to explain the origin of cosmic magnetic fields (MF). Observations show that galaxies have MF with a component coherent over a large fraction of the galaxy with strengths of microGauss order. These MF are supposed to be the result of amplification of initial weak seed MF of unknown nature. Moreover, analysis of the gamma-ray observations from distant blazars together with observations of the cosmic microwave background (CMB) and ultra-high-energy cosmic rays indicates the presence of MF in intergalactic voids of the Universe. Their large coherence length, measured in Megaparsecs, suggests that these MF could have been generated during the earliest stage of the Universe evolution, which is inflation. For now, it is unclear whether MF detected in cosmological voids are helical or not. The answer to this question is very important because it may shed light on possible mechanism of MF generation and their evolution until the present time. In a hot turbulent plasma, helical MF undergo the inverse cascade when the competition between helicity conservation and magnetic diffusion results in the rearrangement of MF spectrum and increase of their comoving correlation length. Helical MF can be amplified in an ultrarelativistic plasma with chiral asymmetry due to the chiral magnetic effect .
We discuss the generation of MF in inflationary models and their evolution in primordial ultrarelativistic plasma with chiral asymmetry, investigate the Schwinger effect in expanding Universe, and analyze the impact of this effect on the process of generation of MF in the early Universe. We try to improve our understanding of the origin of MF and their evolution during the Universe expansion, from the moment of their generation until today, and try to determine which of the inflationary magnetogenesis mechanisms are the most favorable (or excluded) by the present observational data.
We consider a short rollercoaster cosmology based on two stages of monodromy inflation separated by a stage of matter domination, generated after the early inflaton falls out of slow roll. If the first stage is controlled by a flat potential, $V \sim \phi^p$ with $p<1$ and lasts $\mathcal{N} \sim 30−40$ efolds, the scalar and tensor perturbations at the largest scales will fit the CMB perfectly, and produce relic gravity waves with $0.02 \leq r \leq 0.06$, which can be tested by LiteBIRD and CMB-S4 experiments. If in addition the first inflaton is strongly coupled to a hidden sector $U(1)$, there will be an enhanced production of vector fluctuations near the end of the first stage of inflation. These modes convert rapidly to tensors during the short epoch of matter domination, and then get pushed to superhorizon scales by the second stage of inflation, lasting another 20−30 efolds. This band of gravity waves is chiral, arrives today with wavelengths in the range of 108 km, and with amplitudes greatly enhanced compared to the long wavelength CMB modes by vector sources. It is therefore accessible to LISA. Thus our model presents a rare early universe theory predicting several simultaneous signals testable by a broad range of gravity wave searches in the very near future.
Over the past years we have transitioned into a new era of astronomical observations, that of the detection of gravitational waves originating from the coalescence of binary black holes. However, the origin of the detected events remains enigmatic until today. Interesting are the scenarios which probe their dynamical assembly inside of dense stellar systems of astrophysical importance like the globular clusters. We calculate the binary black hole merger rate from Milky Way globular clusters and the contribution from various binary assembly mechanisms is taken into consideration. A few of these channels are dynamical captures, three body binary induce encounters, hardening of a pair and exchange processes. We develop an exchange model and find it to be an efficient way for binary black holes to form in clusters. We present results with applications to primordial black holes and low mass gap objects as motivated by the recent LIGO-Virgo events.
In spite of the extensive search for the detection of the dark matter (DM), experiments have so far yielded null results: they are probing lower and lower cross-section values and are touching the so-called neutrino floor. A way to possibly overcome the limitation of the neutrino floor is a directional sensitive approach: one of the most promising techniques for directional detection is nuclear emulsion technology with nanometric resolution. The NEWSdm experiment, located in the Gran Sasso underground laboratory in Italy, is based on novel nuclear emulsion acting both as the Weakly Interactive Massive Particle (WIMP) target and as the nanometric-accuracy tracking device. This would provide a powerful method of confirming the Galactic origin of the dark matter, thanks to the cutting-edge technology developed to readout sub-nanometric trajectories. In this talk we discuss the experiment design, its physics potential, the performance achieved in test beam measurements and the near-future plans. After the submission of a Letter of Intent, a new facility for emulsion handling was constructed in the Gran Sasso underground laboratory which is now under commissioning. A Conceptual Design Report is in preparation and will be submitted in Summer 2021.
We study how to use Deep Variational Autoencoders for a fast simulation of jets of particles at the LHC. We represent jets as a list of constituents, characterized by their momenta. Starting from a simulation of the jet before detector effects, we train a Deep Variational Autoencoder to return the corresponding list of constituents after detection. Doing so, we bypass both the detector simulation, and the event reconstruction steps of a traditional event processing, potentially speeding up significantly the events generation workflow. Using as benchmark a convolutional VAE, we discuss how to customize the loss to improve accuracy.
The International Masterclass - Hands on Particle Physics is an outreach event proposed by the International Particle Physics Outreach Group since 2004. Its traditional format had a worldwide success during the last years, reaching thousands of high school students and introducing them to the world of particle physics.
During the last two years, the COVID-19 pandemics forced all the groups proposing the activity to find an online alternative to preserve the spirit of the initiative.
The local committee of the University di Trento proposed an online event, divided into several short events carried out over two weeks. The introduction of an analysis challenge among the students has made it possible to obtain a very good response and to achieve, with less than 20 students, enough statistics to discuss the physical results of the analysis. The contribution describes the details of the organization, results, and feedback from the students, with some proposals to improve the experience for the next years.
μΝet aims for the deployment and long-term operation of an extensive school network of educational Cosmic Ray telescopes in the geographical area of Peloponnese. In the framework of μNet, an extended educational program will take place, encompassing educational activities for the construction, testing and operation of μCosmics (microCosmics) detectors, as well as for the remote operation of cosmic ray detection stations and astroparticle physics experimental devices deployed at the Hellenic Open University (HOU) campus. A pilot run of the μNet project started in 2020 aiming for the deployment and operation of a small school network in the prefecture of Achaia. In this report we present briefly the design of the μNet project and report on the results and findings of the pilot run.
The CMS experiment is a collaboration of 242 institutions from 54 countries, and it consists of a community of about 5400 physicists, students, computer scientists, engineers and technicians. As such, diversity is integral to the success of our collaboration. The CMS Diversity Office (DO) is a committee that works to promote diversity as a value for the collaboration, as well as improving the feeling of inclusion of under-represented groups in our work atmosphere. The CMS DO also promotes fairness by highlighting discussions of implicit bias and receiving input from the community. We present some statistics on the composition of the CMS collaboration and the visibility and representation of the diverse talents in leadership and award recognition. In its four years of activity, the CMS DO has implemented a code of conduct for meetings, and participates in CERN Diversity and Inclusion programme, sharing its values and goals.
Liquid argon (LAr) sampling calorimeters are employed by ATLAS for all electromagnetic calorimetry in the pseudo-rapidity region |η| < 3.2, and for hadronic and forward calorimetry in the region from |η| = 1.5 to |η| = 4.9. After detector consolidation during a long shutdown, Run-2 started in 2015 and about 150fb-1 of data at a center-of-mass energy of 13 TeV was recorded. Phase-I detector upgrades began after the end of Run-2. New trigger readout electronics of the ATLAS Liquid-Argon Calorimeter have been developed. Installation began at the start of the LHC shut down in 2019 and is expected to be completed in 2021. A commissioning campaign is underway in order to realise the capabilities of the new, higher granularity and higher precision level-1 trigger hardware in Run-3 data taking. This contribution will give an overview of the new trigger readout commissioning, as well as the preparations for Run-3 detector operation.
The ATLAS experiment is currently upgrading the first muon station in the high-rapidity region with the New Small Wheels (NSW), based on large-size multi-gap resistive strips Micromegas technology and small-strip Thin Gap Chambers (sTGC).
The NSW system is going to be installed in the ATLAS underground cavern during the LHC long shutdown 2 (2021) to enter in operation for Run3 (starting in February 2022). 128 Micromegas quadruplets, each composed by four measurement layers two square meters in size, are needed to build the two New Small Wheels, covering a total active area of about 1280 m2. The construction of all MM modules, carried out in France, Germany, Italy, Russia and Greece, is completed. Their mechanical integration into sectors, the installation of on-detector services and electronics, for the first NSW is also completed, along with all validation and acceptance tests. The preparation of the second NSW is very well advanced.
The advanced status of the project, in view of the imminent installation of the two NSW in ATLAS by the fall of 2021 will be reported.
The presentation will describe the integration workflow of Micromegas detector into sectors and will focus on the results obtained with cosmic rays data during the final validation tests. Finally, the impressive steps of the wheel assembly completion, will be shown.
Being state-of-the-art, the Micro-Pattern Gaseous Detectors (MPGD) are widely accepted in several particle physics experiments like ATLAS, COMPASS, CMS, ALICE, CBM, EIC, ILC, etc. Micromegas is a type of MPGD which is famous for its simple single-stage amplification, high and stable gain, low ion feedback, and excellent spatial and temporal resolutions. It is a reliable candidate in many of the aforementioned experiments. The chance of O2 contamination in a gaseous detector gas is not negligible as the abundance of O2 in the air is nearly 21%. Being an electronegative gas, O2 can capture electrons inside a gaseous detector. Therefore, while running a gaseous detector of large size, O2 contamination, even at a very low concentration, may degrade the detector performance. We have systematically studied one of the possible reasons for O2 contamination of the gas inside a detector. Then by infusing O2 inside a resistive Micromegas chamber in a controlled and precise way, we have studied its effects on the fluctuation of primary electrons and on the instability of gas-gain of the detector. Both aspects of our study have been supported by numerical investigations.
Kalliopi Petrou (soprano), Elia Sempere (Piano)
The LIGO and Virgo observatories are delivering an unprecedented view of the populations and properties of black holes and neutron stars by observing the universe through gravitational waves. Measuring gravitational waves requires incredible physics to detect incredible astrophysics. This talk will detail the characteristics of LIGO's long baseline optical interferometers, the upgrades planned to improve them, and the commissioning efforts to improve their data quality.
Cosmological models and the processes accompanying the cosmic rays propagation on cosmological scales are considered on the basis of particle dynamics, electrodynamics and general relativity (GR) developed from the basic concepts of the 'relativity with a preferred frame'. The 'relativity with a preferred frame', designed to reconcile the relativity principle with the existence of the cosmological preferred frame, incorporates the preferred frame at the fundamental level of special relativity (SR) while retaining the fundamental space-time symmetry which, in the standard SR, manifests itself as Lorentz invariance. The cosmological models based on the modified GR of the 'relativity with a preferred frame' allow to explain the SNIa observational data without introducing the dark energy and also fit other observational data, in particular, the BAO data. Applying the theory to the photo pion-production and pair-production processes, accompanying the propagation of the Ultra High Energy Cosmic Rays (UHECR) and gamma rays through the universal diffuse background radiation, shows that the modified particle dynamics, electrodynamics and GR lead to measurable signatures in the observed cosmic rays spectra which can provide an interpretation of some puzzling features found in the observational data. Other possible observational consequences of the theory, such as the birefringence of light propagating in vacuo and dispersion, are discussed.
With an ever growing number of observed compact binary coalescences, LIGO and Virgo are enabling ever more precise tests of the fundamental nature of spacetime. Our ability to test general relativity in the strong field regime is driven by the signal-to-noise ratio of the individual observed binaries as well as the heterogeneity of the underlying astrophysical population of binary black holes. In this talk, I will summarize the status of testing general relativity with gravitational wave observations, including results from the second LIGO-Virgo catalog (GWTC-2), which has yielded some of our best constraints to date on the fundamental properties of astrophysical black holes. I will highlight future prospects for testing general relativity as well as some of the open questions and challenges that will play an increasingly important role in this rapidly evolving field of research.
We study the in-medium effects in strangeness production in heavy-ion collisions at (sub-)threshold energies of 1 - 2 A GeV based on the microscopic Parton-Hadron-String Dynamics (PHSD) transport approach. The in-medium modifications of the antikaon ($\bar K = K^-, \bar K^0$) properties are described via the self-consistent coupled-channel unitarized scheme based on a SU(3) chiral Lagrangian which incorporates explicitly the $s−$ and $p−$ waves of the kaon-nucleon interaction. This scheme provides the antikaon potential, spectral functions and reaction cross sections as well as their dependence on baryon density, temperature and antikaon momentum in the nuclear medium, which are incorporated in the off-shell dynamics of the PHSD. The in-medium modification of kaons ($K = K^+,K^0$) are accounted via the kaon-nuclear potential, which is assumed to be proportional to the local baryon density. The manifestation of the medium effects in observables is investigated for the $K$ and $\bar K$ rapidity distributions, $p_T$ -spectra as well as the polar and azimuthal angular distributions, directed ($v_1$) and elliptic ($v_2$) flow in C+C, Ni+Ni, and Au+Au collisions. We find - by comparison to experimental data from the KaoS, FOPI and HADES Collaborations - that the modifications of (anti)kaon properties in nuclear matter are necessary to explain the data in a consistent manner. Moreover, we demonstrate the sensitivity of kaon observables to the equation-of-state of nuclear matter.
“Ice in fire” is called the phenomenon that in heavy ion collisions at midrapidity clusters have been observed. Their existence is unexpected because objects with a small binding energy (ice) with respect to the temperature of the expanding fireball (fire) should not be formed at all. Applying the recently advanced PHQMD model, which unites the n-body dynamics of nucleons with the collision integrals and the description of the QGP of the PHSD model we studied the formation of clusters and find that from a kinetic energy of 1.5 AGeV until a center of mass energy of 200 GeV the process of cluster formation is rather similar. We compare our results with the available data and investigate in detail how the cluster survive the expansion of the fireball at midrapidity.
Searches for supersymmetry in CMS detector are addressed. The searches target a number of diverse production modes of the supersymmetric particles decaying into a variety of final states. The latest results using the proton-proton collision data with luminosity up to 137 fb-1 recorded by the CMS detector at center of mass energy 13 TeV during the LHC Run 2 are presented.
Supersymmetry (SUSY) provides elegant solutions to several problems in the Standard Model, and searches for SUSY particles are an important component of the LHC physics program. This talk will present the latest results from searches conducted by the ATLAS experiment, covering both strong and electroweak SUSY particle production processes. The searches target multiple final states and different assumptions about the decay mode of the produced SUSY particles, including searches for both R-parity conserving models and R-parity violating models and their possible connections with the recent observation of the flavour and muon g-2 anomalies. The talk will also highlight the employment of novel analysis techniques, including advanced machine learning techniques and special object reconstruction, that are necessary for many of these analyses to extend the sensitivity reach to challenging regions of the phase space.
The ATLAS experiment has performed measurements of B-meson rare decays proceeding via suppressed electroweak flavour changing neutral currents, and of mixing and CP violation in the neutral Bs meson system. This talk will focus on the latest results from the ATLAS collaboration, such as rare processes B0s → mu mu and B0 → mu mu, and CP violation in the B0s —> J/psi phi decays. In the latter, the Standard Model predicts the CP violating mixing phase, phi_s, to be very small and its SM value is very well constrained, while in many new physics models large phi_s values are expected. The latest measurements of phi_s and several other parameters describing the B0s —> J/psi phi decays will be reported.
The presence of a non-baryonic Dark Matter (DM) component in the Universe is inferred from the observation of its gravitational interaction. If Dark Matter interacts weakly with the Standard Model (SM) it could be produced at the LHC. The ATLAS experiment has developed a broad search program for DM candidates, including resonance searches for the mediator which would couple DM to the SM, searches with large missing transverse momentum produced in association with other particles (light and heavy quarks, photons, Z and H bosons) called mono-X searches and searches where the Higgs boson provides a portal to Dark Matter, leading to invisible Higgs decays. The results of recent searches on 13 TeV pp data, their interplay and interpretation will be presented. Prospects for HL-LHC will also be discussed.
We investigate FASER@LHC perspectives in searches for light ($0.1-4$ GeV)
sgoldstinos in models with low energy ($10-10^4$\,TeV) supersymmetry
breaking. We consider flavor conserving and flavor violating coupling of
sgoldstinos to Standard Model fermions and find both options to be
testable at FASER. Even the first FASER run allows one to probe
interesting patches in the model parameter space, while the second run,
FASER-II, with signnificantly larger detector fiducial volume, gives a
possibility to thoroughly explore a wide class of supersymmetric
extensions of particle physics complementary to those probed at LHC with
ATLAS and CMS detectors.
The SM process where four top quarks are produced in proton-proton collisions is very rare process with a cross section of the order of 12 fb^{-1} at NLO accuracy in QCD+EWK. Studies of this process can provide limits to the top—quark Yukawa coupling using limits on the cross section. In addition, it is expected to provide insight to many BSM as these models modify the production of four tops. Using the data collected during the Run 2 of the LHC the CMS Collaboration is studying this rare process. Several decay channels are looked at and the results are combined to push the expected significance of four-tops production above the 3 standard-deviations (sigma).
In recent years, Machine Learning (ML) methods have become ubiquitous in High Energy Physics (HEP) research. This talk will explore current areas of ML for HEP research including event classification, object reconstruction, jet tagging, and accelerated ML inference for trigger environments. I will also discuss current opportunities and challenges in the ML for physics space and ways researchers can use these tools to advance science. Although this talk is focused on successful implementations of novel ML methods in the CMS experiment, the techniques and topics covered are relevant to a wide range of HEP experiments.
The ZnWO$_4$ crystal scintillators are promising detectors for low counting experiments thanks to the high level of radio-purity, and reasonably high optical and scintillation properties. Moreover, ZnWO$_4$ is an anisotropic scintillator which can offer a unique possibility to exploit the so-called directionality approach in order to investigate the presence of Dark Matter candidates that induce nuclear recoils. In addition to Dark Matter investigations, the ZnWO$_4$ scintillators can be used in the searches for other rare processes, as double beta processes in zinc ($^{64}$Zn, $^{70}$Zn) and tungsten ($^{180}$W, $^{186}$W) nuclides, and in the investigations of the alpha decay of $^{180}$W. The goal of the ADAMO project is the development of ZnWO$_4$ crystal scintillator with high radiopurity, the optimization of the detector performance and the study of its anisotropic response to nuclear recoils. In this talk, the recent results obtained by the ADAMO project will be reviewed.
The next generation of x-ray satellite missions, like XRISM or Athena, will be equipped with state-of-the-art instrumentation, delivering high-resolution spectra. However, the accuracy of parameters like elemental composition, velocity, density, and temperature will be limited by the uncertainties and availability of atomic data, like line positions, line strengths, and cross-sections for different atomic-scale processes. Reliable access to these quantities is necessary to gain insight into formation and evolution of hot astrophysical objects, like active galactic nuclei (AGN), in which accretion of mass onto super-massive black holes and mass outflows provide feedback mechanisms during the co-evolution of AGNs with their host galaxies.
PolarX-EBIT is a compact electron beam ion trap (EBIT), based on an assembly of room-temperature permanent magnets [1]. It uses a monoenergetic electron beam to generate highly charged ions (HCI) by stepwise electron impact ionization. These ions form a stationary prolate ion cloud, which can be used as a target for ultrabrilliant x-ray photon beams from synchrotrons and free-electron laser (FEL) light sources. A novel off-axis electron gun allows the photon beam to leave the interaction region and be made available for downstream setups. This enables high-precision spectroscopy experiments, providing atomic data for processes involving resonant photoexcitation for a wide range of ion species, commonly found in different astrophysical plasmas.
We present results of experiments conducted at the synchrotron facilities PETRA III in Hamburg, with PolarX-EBIT’s regular site of operation at beamline P01, and BESSY II in Berlin. The measurements provided relative line strengths and bounds for natural line widths of transitions in Ne-like Fe$^{16+}$ [2], revealed strong two-electron-one-photon (TEOP) transitions in Li-like O$^{5+}$ [3], uncovered a previously unknown systematic energy shift in widely used reference spectra in the soft x-ray regime [4], and demonstrated the potential of emission from metastable excited states in HCI as tool for spectroscopic plasma density diagnostics.
[1] P. Micke et al., Rev. Sci. Instrum. 89, 063109 (2018).
[2] S. Kühn et al., Phys. Rev. Lett. 124, 225001 (2020).
[3] M. Togawa et al., Phys. Rev. A 102, 052831 (2020).
[4] M. A. Leutenegger et al., Phys. Rev. Lett. 125, 243001 (2020).
The nature of dark matter (DM) is one of the most fascinating unresolved challenges of modern physics. One of the perspective hypotheses suggests that DM consists of ultralight bosonic particles in the state of Bose-Einstein condensate (BEC). The superfluid nature of BEC must dramatically affect the properties of DM including quantization of the angular momentum. Angular momentum quantum in the form of a vortex line is expected to produce a considerable impact on the luminous matter in galaxies including density distribution and rotation curves.
We investigate the general properties and stability of spinning DM cloud with typical galactic halo mass and radius. Analytically and numerically stationary vortex soliton states with different topological charges have been analyzed. It has been shown that while all multi-charged vortex states are unstable, a single-charged vortex soliton is extremely robust and survives during the lifetime of the Universe.
Binary collisions between two spinning DM clouds are then studied. Remarkably, vortex solitons may pass right through each other in a quasi-elastic head-on collision. The interacting BEC clouds display an interference pattern as they pass through each other, recovering their vortex identities after the collision. Since the vortex solitons appear to be very robust structures it opens a perspective for their observation in the Universe for different scales: from bosonic stars to large-scale galactic haloes.
The number density of small dark matter (DM) halos hosting faint high-redshift galaxies is sensitive to the DM free-streaming properties. However, constraining these DM properties is complicated by degeneracies with the uncertain baryonic physics governing star formation.
We use a flexible astrophysical model and a Bayesian inference framework to analyse ultra-violet (UV) luminosity functions (LFs) at $z=6-8$. We vary the complexity of the astrophysical galaxy model as well as the matter power spectrum (cold DM vs thermal relic warm DM), comparing their Bayesian evidences.
Adopting a conservatively wide prior range for the WDM particle mass, we show that the UV LFs at $z=6-8$ only weakly favour CDM over WDM. We find that particle masses ≲2 keV are rejected at a 95% credible level in all models that have a WDM-like power spectrum cutoff. This bound should increase to $\sim2.5$ keV with the James Webb Space Telescope (JWST).
The search for sources of ultra high energy cosmic rays (UHECR) remains one of the main unsolved problems in modern astrophysics. Galactic magnetars are promising candidates for the UHECR accelerators due to their ability to generate relativistic plasma flows and shock waves during magnetar giant flares. Such energetic processes in plasma also occurs during a Supernova ejecta energisation and a magnetar wind nebulae (MWNe) formation by newborn millisecond magnetars. In both cases, typical signatures of particle acceleration are neutrino and broad-band (from the radio to gamma-ray ) non-thermal emission. This non-thermal emission is either the result of hadronic or leptonic mechanism. In the first case, radiation is the outcome of proton-proton collisions $pp \rightarrow \pi_0 \pi^+ \pi^- + all $, with the subsequent decay of neutral pions into gamma-rays $\pi_0 \rightarrow \gamma \gamma$ and charged pions into neutrinos $\pi^+ \pi^- \rightarrow \nu_{\mu} \nu_{e} + all$. Leptonic emission is the result of synchrotron radiation and energy transfer to background photons from ultrarelativistic electrons (the inverse Compton scattering). In this work we show that high-energy and very high-energy gamma-ray emission from the magnetar SGR1900+14 region can be explained by the acceleration of cosmic rays in the magnetar-connected Supernova remnant and/or MWN. Moreover, detected by Auger and Telescope Array positionally coincident triplet of UHECR with $E>10^{20}$ eV, can be accelerated in giant flare of the SGR1900+14. To achieving necessary energy reserve, the SGR1900+14 progenitor must be the newborn millisecond magnetar with initial rotational energy $E_{rot} \sim 10^{52}$ erg.
Blazars – active galactic nuclei (AGN) with their relativistic jets pointing towards the observer – dominate the extragalactic high-energy (E > 100 MeV) gamma-ray sky. It is believed that gamma rays in AGN are mostly produced in the so-called “blobs” – relativistic clouds of magnetized plasma propagating along the AGN jets.
Flat-spectrum radio quasars (FSRQs) are powerful blazars believed to contain broad line region (BLR) matter in the form of wind or clouds. The location of gamma-ray emission sites in FSRQs is uncertain. The MAGIC collaboration reported the detection of FSRQ PKS 1510-089 in its low (persistent) state of activity [Acciari et al., A&A, 619, A159 (2018)]. It is very unlikely that this low-state emission could have formed in one or two distinct blobs, so we assume that the emission has formed either in the jet itself or in many blobs.
In our work we investigate the location of the gamma-ray production site and the production mechanism of these gamma rays in the low state of PKS 1510-089. We perform Fermi Large Area Telescope (Fermi-LAT) data analysis using 12 years of its data and distinguish between the low and the high states of gamma-ray emission of PKS 1510-089. We obtain the spectral energy distribution (SED = E^{2}dN/dE) of PKS 1510-089 averaged over its low-state periods and combine it with the SED measured with the MAGIC telescopes during the low-state period of PKS 1510-089.
We show that in the energy range from 100 MeV to 10 GeV the observed SED is well described with a log-parabolic gamma-ray spectrum, but at E > 10 GeV some excess is apparent. A possible scenario that could explain this excess includes primary proton interactions with BLR matter resulting in the production of secondary gamma rays. If this scenario is confirmed, it would provide evidence for: 1) acceleration of protons or nuclei in blazar jets, 2) interaction of these hadrons with the BLR matter in FSRQs, and 3) the production of sub-TeV gamma rays in FSRQs near the edge of the BLR.
The reported study was funded by RFBR, Russia, project number 20-32-70169.
PANDA is a hadron physics research detector at the FAIR facility in Darmstadt, using antiproton beams with momenta between 1.5 and 15 GeV/c interacting with fixed proton targets. From the scientific requirements, the high-performance of electromagnetic calorimeters (EMC) is of utmost importance for the success of the PANDA experiment. Excellent identification and reconstruction of multi-photon/lepton events are crucial for the study of resonances decaying to pi0/eta, photons or electrons. In addition, final states with many photons can occur, leading to a low photon threshold as a central requirement for the EMC. To measure wide angle Compton scattering, the detection of high energy photons is also needed. Thus, high-performance of EMC over a large energy range from a few MeV up to several GeV is required. To achieve these requirements from software side, a dedicated calibration method including Machine Learning, is developed. This talk presents the calibration strategies and the implementation to Monte Carlo simulated data sample. After calibration, high-performance of PANDA EMC can be achieved with improved energy scale stability and resolution.
Deep machine learning methods have been studied for the PANDA software trigger with data sets from full Monte Carlo simulation using PandaRoot. Following the first comparison of multiclass and binary classification, the binary classification has been selected because of higher signal efficiencies. In total seven neural network types have been compared and the residual convolutional neural network with 4 residual blocks has been chosen. The results of optimized neural networks and those of the conventional method have been compared, showing an efficiency gain of up to 140% for the deep machine learning method. The flatness quality parameters on Dalitz plots and theta-phi projections have been obtained.
Based on a number of features from proton-proton collisions taken during Run 1 data taking period at the LHC, a boson with a mass around the Electro-Weak scale was postulated such that a significant fraction of its decays would comprise the Standard Model (SM) Higgs boson and an additional scalar, S. One of the implications of a simplified model, where S is treated a SM Higgs boson, is the anomalous production of high transverse momentum leptons. Corners of the phase-space are fixed according to the model parameters derived in 2017 without additional tuning, in order to nullify potential look-else-where effects or selection biases. A combined study of subsequent data is indicative of significant discrepancies between the data and SM Monte Carlos in a variety of final states involving multiple leptons with and without b-quarks. These discrepancies appear in corners of the phase-space where different SM processes dominate, indicating that the potential mismodeling of a particular SM process is unlikely to explain them. The internal consistency of these anomalies and their interpretation in the framework of the original hypothesis is quantified. Implications on the Higgs boson measurements, muon g-2 and and astrophysics are also discussed. A narrow structure in the di-photon and Zphoton spectra will also be presented.
The determination of charged-particle trajectories (tracking) and the identification of primary collision vertices (vertexing) are complex parts of the event reconstruction chain in collider experiments and constitute the building blocks of most high level analysis objects. During the Run 2 data-taking in ATLAS, tracking was by far the most resource intensive step, for an average number of p-p collisions per bunch crossing (pile-up) ranging from 20 up to 60. The complexity of the combinatorial problem increases dramatically with pile-up and the physics performance degrades as more low-quality tracks with mis-assigned, missing or randomly combined hits are reconstructed.
Averages of around 50 interactions per bunch-crossing are expected during the LHC Run 3, rising to about 200 during the High-Luminosity (HL) phase of the LHC, scheduled to start in about 5 years.
In order to cope with these challenging conditions and to maintain the physics performance reached up to LHC Run 2, a major rewrite of the Run 3 reconstruction software was performed while ATLAS prepares for a replacement of the current ATLAS Inner Detector with a new all-silicon Inner Tracker (ITk) for HL-LHC.
The Run 3 software improvements allowed to dramatically increase the reconstruction speed and pileup robustness. This included replacing the existing ATLAS vertexing with the pioneering use of elements of the ACTS software framework, which will become the backbone of ITk track reconstruction, in production.
In this talk, the improvements achieved for the track and vertex reconstruction to be used in the upcoming LHC Run 3 as well as the latest results on the expected performance of the ITk tracking and of other high-level object identification will be presented.
Does inflation have to happen all in one go? The answer is a resounding no! All cosmological problems can be solved by a sequence of short bursts of cosmic acceleration, interrupted by short epochs of decelerated expansion. The spectrum of perturbations will still match the CMB and LSS if the earliest stage of the last ${\cal O}(50)-{\cal O}(60)$ efolds is at least ${\cal O}(15)$ efolds long. Other stages can be considerably shorter. But as long as they add up to ${\cal O}(50)-{\cal O}(60)$ efolds and the stages of decelerated expansion in between them are shorter and also overall last less, the ensuing cosmology will pass muster. The presence of the interruptions resets the efold clock of each accelerating stage, and changes its value at the CMB pivot point. This change opens up the theory space, loosening the bounds. In particular some models that seem excluded at ${\cal N}=60$ fit very well as shorter stages with ${\cal N}=30$. Interesting predictions are that both the scalar and tensor spectra of perturbations are rapidly modified at short wavelengths. In the simplest cases the perturbations are suppressed relative to the perturbations at large scales just because when they freeze out, the background curvature is smaller. The modes which do leave the horizon however will remain frozen as long as the subsequent intervening stages of decelerated expansion remain short. These features could be tested with future CMB spectroscopy searches and with short wavelength primordial gravity probes. The spatial curvature in these models can be larger than the largest wavelength scalar perturbations, because $\Omega_{\tt k}$ evolves differently than the scalar perturbations $\frac{\delta \rho}{\rho}|_{\tt S}$. Finally, with many short stages of accelerated expansion, the abundance of reheating products from previous accelerated stages does not get completely wiped out. This implies that the universe may contain additional populations of particles, more rare than the visible ones, or even primordial black holes, created during a late decelerated epoch before last reheating, which may be dark matter.
Elliptic $\varepsilon_2$ and triangular $\varepsilon_3$ eccentricities
arising in initial state of relativistic heavy-ion collisions are
studied within the framework of a geometrical model with event-by-event
fluctuations. Elliptic eccentricity is shown to be determined mainly
by the average collision geometry, whereas the triangular one is
related merely to the fluctuations. Assuming the linear dependence of
the second $v_2$, and third, $v_3$, harmonics of anisotropic flow on
$\varepsilon_2$ and $\varepsilon_3$, respectively, the model provides
a fair description of the ALICE results for Pb+Pb collisions at
$\sqrt{s_{NN}} = 5.02$ TeV. Similar to spatial eccentricities, elliptic
flow weakly depends on the fluctuations everywhere but in very central
collisions, while triangular flow is mostly determined by the
event-by-event fluctuations. For the collisions with centrality 0-2\%
a novel scaling dependence for the magnitudes of the flow harmonics
$v_n$ on atomic number $A$, $v_n \propto A^{-1/3}$, is predicted.
This prediction agrees well with the available experimental data.
The development of metallic magnetic calorimeters (MMCs) has resulted in a new class of detectors for precision X-ray spectroscopy such as the maXs detectors [1] (cryogenic micro-calorimeter arrays for high resolution X-ray spectroscopy experiments at FAIR), being developed within the SPARC collaboration. MMCs are energy dispersive detectors which combine the very high energy resolution comparable to crystal spectrometers (1.7 eV FWHM at 6 keV [2] and 50 eV FWHM at 100 keV within this experiment) with the broad bandwidth acceptance of semiconductor detectors (0.1 – 100 keV) [3]. This is achieved by their unique measurement principle: at operating temperatures below 50 mK, the temperature rise caused by the absorption of an incident X-ray photon in an absorber leads to a change in the magnetisation of a paramagnetic sensor which can be measured by a superconducting quantum interference device (SQUID) [4]. By using these extraordinary capabilities, the $^{229}$Th isomeric energy has recently been determined with unprecedented precision [5].
In this contribution we present the first application of maXs-type detectors for high resolution X-ray spectroscopy at CRYRING@ESR, the low energy storage ring of GSI, Darmstadt. Within the experiment, X-ray radiation emitted as a result of recombination events between the electron cooler electrons and a stored beam of U$^{91+}$ ions was studied. For this purpose, two maXs detectors were positioned at the electron cooler under observation angles of 0° and 180° with respect to the ion beam axis. This report will focus on details of the experimental setup, its performance and its integration into the storage ring environment. Noteworthy aspects are a quasi-continuous energy calibration, as well as the first usage of the time resolution of the maXs detectors to achieve a coincidence measurement with a particle detector.
This research has been conducted in the framework of the SPARC collaboration, experiment E138 of FAIR Phase-0 supported by GSI. We acknowledge substantial support by ErUM-FSP APPA (BMBF n° 05P19SJFAA).
References
[1] C. Pies et al., maXs: Microcalorimeter Arrays for High-Resolution X-Ray Spectroscopy at GSI/FAIR, J Low Temp Phys 167, 269–279 (2012)
[2] S. Kempf et al. Physics and Applications of Metallic Magnetic Calorimeters. J Low Temp Phys 193, 365–379 (2018)
[3] A. Fleischmann et al., Cryogenic Micro-Calorimeter Arrays for High Resolution X-ray Spectroscopy Experiments at FAIR, technical design report, https://fair-center.eu/fileadmin/fair/publications_exp/TDR_maXs_public_2016_02_11.pdf, (2016)
[4] D. Hengstler et al., Towards FAIR: first measurements of metallic magnetic calorimeters for high resolution X-ray spectroscopy at GSI, Phys. Scr. T166, 014054 (2015)
[5] T. Sikorsky et al., Measurement of the $^{229}$Th Isomer Energy with a Magnetic Microcalorimeter, Phys. Rev. Lett. 125, 142503 (2020)
The sentence length (number of words/syllables in a sentence) distributions of texts (novels, speeches, etc), vary between different languages and different persons (authors or speakers). In this paper we proposed an entropy method based on the sentence lengths of texts, to explore the characteristics of the English and Chinese languages, and the different persons. The main results show that significant differences are found between the two languages and between different persons. The entropy analysis points in the direction of lower entropy, that is of higher complexity.
Chiral and SU(3) symmetry breaking in the non perturbative regime is approached with lattice calculation and effective field theories, but still lacking experimental results especially in the strangeness sector, leaving unanswered questions in nuclear, particle and astrophysics. To this end, kaon-nucleon/nuclei scattering interaction has traditionally been studied by scattering measurements at low-energy; however experimental data below 100 MeV/c are scarse and suffer from large uncertainties, making theoretical model validations difficult. Measurements of transitions in atomic systems, such as kaonic hydrogen and kaonic deuterium, provide a unique tool to extract the isospin-dependent kaon-nucleon scattering at threshold. The SIDDHARTA2 experiment at LNF-INFN DAFNE e+ e- collider is starting its data taking campaign, aiming at performing the first high precision measurement of kaonic deuterium X-Rays transitions to the fundamental level. The scientific case, experimental challenges as well as the outlook of possible future measurements of the SIDDHARTA2 experiment will be discussed.
The study of low-energy antinucleons interactions with nuclei are of great interest for many branches of physics. In particular, information on nuclear elastic scattering and annihilation can give some clues to answer open questions like antimatter-matter asymmetry in the Universe and provide useful information for quark and nuclear interactions models.
Moreover, the determination of scattering length of antineutrons is useful for the realization of experiments to search neutron-antineutron oscillations, a hypotetical phenomenon of great importance in the particle physics and cosmology scenario. This quantity can be deduced by antinucleon cross sections data with nuclei.
Another intriguing question regards the annihilation cross-section of antiprotons and antineutrons with nuclei, which seem to be very similar at low-energies. This behaviour is counter-intuitive and the mechanism responsible of it still unknown, and therefore more precise study of annihilation models for antinucleons is required.
In this presentation, recent experimental and theoretical results on antinucleon cross-section at low energies are considered.
New calculations with partial wave method and using a Woods-Saxon optical potential for annihilation and nuclear elastic cross-sections are presented. The study concerns the momentum region from 1 to 100 MeV/c. The behaviour of the mentioned processes and the different parital waves contributions are discussed.
Particle-particle correlations, either rapidity-rapidity or rapidity-azimuthal angle correlations was already an important tool for hadron collider physics since the early 70s. Recently, we studied one-particle rapidity distributions and two- particle rapidity-rapidity correlations at hadron colliders revisiting one of the old models, the Chew-Pigniotti multiperipheral model and we were surprised to realize that the predictions were very much in line with the predictions one gets for the minijet radiation by using perturbative high energy QCD. Here, we report on results from studying rapidity-rapidity and rapidity-azimuthal angle correlations at proton-proton collisions using the Monte Carlo code BFKLex.
The NA62 experiment at CERN collected a large sample of charged kaon decays into final states
with multiple charged particles in 2016-2018. This sample provides sensitivities to rare decays with
branching ratios as low as 10-11.
Results from searches for lepton flavour/number violating decays of the charged kaon and the neutral pion to final states containing a lepton pair based on this data set are presented.
With the PICR hydrodynamic model, we study the polarization splitting between $\Lambda$ and $\bar{\Lambda}$ at RHIC BES energy range, based on the meson field mechanism. Our results fit to the experimental data fairly well.
Besides, two unexpected effect emerges: (1) the baryon density gradient has non-trivial and negative contribution to the polarization splitting; (2) for 7.7 GeV Au+Au collisions within the centrality range of 20\%-50\%, the polarization splitting surprisingly increases with the centrality decreases. The second effect might help to explain the significant signal of polarization splitting measured in STAR's Au+Au 7.7 Gev collisions..
The decay K+→π+ νν ̅ , with a very precisely predicted branching ratio of less than 10-10, is among
the best processes to reveal indirect effects of new physics.
The NA62 experiment at CERN SPS is designed to study the K+→π+ νν ̅ decay and to measure its
branching ratio using a decay-in-flight technique. NA62 took data in 2016, 2017 and 2018, reaching
the sensitivity of the Standard Model for the K+→π+ νν ̅ decay by the analysis of the 2016 and
2017 data, and providing the most precise measurement of the branching ratio to date by the
analysis of the 2018 data. This measurement is also used to set limits on BR(K+→π+X), where X is
a scalar or pseudo-scalar particle.
The final result of the K+→π+ νν ̅ branching ratio measurement and its interpretation in terms of
K+→π+ X decay from the analysis of the full 2016-2017-2018 data set is presented, and future plans and prospects reviewed.
We work on the important signature of quark gluon plasma (QGP)where effective quark mass incorporate in place of finite quark mass. Two photon spectra is plotted using quasiparticle treatment. The result from finite value of quark mass and effective quark mass are found almost same. This indicate that our calculation are not invalidate with the effect of effective mass of quark.
Therefore our result are fitted nicely and doesn't diverse in the presence of effective quark mass. The study is useful to explore more about the electromagnetic signals.
Predictions for the global Λ polarization in Au+Au collisions in current and upcoming experiments at moderately relativistic energies, 2.4 ≤ √s_NN ≤ 12 GeV, are made. The simulations were performed within the model of the three-fluid dynamics with three different equations of state. It is predicted that the global polarization increases with the collision energy decrease. At √s_NN ≈ 3 GeV this increase slows down or even a maximum is reached, depending on the centrality. Expansion of the rapidity window, in which the polarization is measured, results in the global polarization increase. This indirectly indicates that the global polarization is larger outside the midrapidity region than that in the midrapidity. Possibility of measuring the polarization of hyperons at moderately relativistic collision energies, which are and will be available at various laboratories, are analyzed. Whereas the collision dynamics becomes less equilibrium with the collision energy decrease, all presently available approaches to the particle polarization are based on the assumption of thermal equilibrium. Therefore, the problem of thermalization in nuclear collisions is analyzed. It is found that the equilibrium is achieved at the freeze-out stage, only this equilibration takes longer at moderately relativistic energies.
The short-lived hadronic resonances are used to study the properties of the hot and dense medium produced in relativistic heavy-ion collisions. The resonance lineshapes (masses and widths), yields and mean transverse momenta measured in the hadronic decay channels are sensitive to different stages of the nuclear collisions. Having different masses, strangeness content and baryonic numbers, they contribute to the study of strangeness production, reaction dynamics and particle production mechanisms in different momentum ranges. Resonances are most useful in the study of the lifetime and density of the late hadronic phase.
In this talk, we review the expected properties of short-lived resonances in heavy-ion collisions at NICA energies with a focus on the line shape modifications and their consequences for the extracted yields and shapes of the production spectra. We also present new results on the possibility to reconstruct $K^{*}(892)^{\pm}$, $\Sigma$(1385)$^{\pm}$ and $\Xi$(1530)$^{0}$, which have weakly decaying daughters in the intermediate stages of the decays, in the MPD detector in Au+Au collisions at $\sqrt{s_{NN}}$ = 4-11 GeV.
Photons serve as valuable probes of the properties of the hot and dense nuclear matter created in collisions of heavy ions. Thermal photon spectra at RHIC and LHC energies indicate that the temperature of the produced medium far exceeds the temperature of the phase transition to the quark-gluon plasma in lattice QCD calculations. Measurements of thermal photon spectra in heavy ion collisions at lower energies at the future NICA collider may help to trace the transition from partonic to hadronic degrees of freedom. In this contribution, feasibility studies on thermal photon measurements using the photon conversion method in the future MPD experiment at NICA will be reviewed. A possibility to increase photon reconstruction efficiency with a dedicated conversion layer will be presented and feasibility to probe the material budget of the experiment with converted photons will be discussed.
Heavy quarks (i.e, charm and bottom) are produced at the very early stage of high energy nucleon-nucleon and heavy-ion collisions. These heavy quarks are produced mainly through initial hard parton-parton scattering with large momentum transfer (Q$^2$). In relativistic heavy-ion collisions, the heavy
quarks are produced much before the formation of deconfined medium consisting of quarks and gluons called Quark Gluon Plasma (QGP). The heavy quarks experience the full evolution by propagating through the medium and loses energy by successive elastic and inelastic collisions in that medium. Hence, heavy quarks are very sensitive probe to study the mechanisms of parton-energy loss, hadronisation and the transport properties of the medium produced in high energy heavy-ion collisions. In LHC (Large Hadron Collider) energies, the study of few features of heavy-ion collisions is possible in proton-proton collision. The production of heavy quarks through the hard process, can be described via theoretical model such as perturbative QCD (pQCD) calculations. Therefore, the measurement of heavy quarks in proton-proton (p-p) collisions provides an important test for pQCD and serves as a baseline for proton-ion (p-A) and ion-ion (A-A) collisions. In LHC, additional activities other than hard scattering are Underlying Event (UE) observables. One of the frequently used theoretical aspect of UE is multiple partonic interactions (MPI) based on non-pQCD system which deals with low momentum transfer in soft process. This softer partonic scatters (MPI) have significant contribution on total event multiplicity in high energy p-p collisions. MPIs are often described as the soft processes where light quarks are mainly produced, but there can be a contribution from hard and semi-hard scales. Semi-hard multiparton interactions are expected to be relevant for hard processes at LHC energies and contribute to heavy flavour particles production. In the link between hard and soft processes, the initial state and final state correlations may help understanding the origin of collectivity in small systems like p-p, p-A collisions. Few features like strangeness enhancement and formation of ridge strongly support the evidence of collective origin in high multiplicity p-p collisions. A charged-particle multiplicity dependent production measurement in p-p collision allows to study the interplay between soft and hard particle production mechanisms. To investigate the role of MPI on hard scale, one can study the heavy flavour production as a function of charged-particle multiplicity in p-p collisions at LHC energy regimes.
We shall present the production of leptons from heavy-flavour hadron decay as a function of charged-particle multiplicity in p-p collisions at LHC energies using PYTHIA8 event generators. The open heavy-flavour hadrons via their semi-leptonic decay channels are to be measured in central region ($|\eta| <$ 0.8) with electrons and at forward region ($−4. < \eta < −2.5$) with muons. The incorporation of MPI in PYTHIA8 may allow a good qualitative description of the multiplicity distribution. There is another frequently used phenomenological model which is called colour reconnection (CR) model. The collectivity in small systems has been studied with CR model. In PYTHIA8, there are three different models available for colour reconnection such as (i) MPI based model (CR=0), (ii) New QCD model (CR=1) and (iii) Gluon move model (CR=2). We shall add the CR model in the pythia8 simulation to estimate systematic uncertainties of our analysis.
The Phase-II upgrade of the LHC will increase its instantaneous luminosity by a factor of 7 leading to the High Luminosity LHC (HL-LHC). At the HL-LHC, the number of proton-proton collisions in one bunch crossing (called pileup) increases significantly, putting more stringent requirements on the LHC detectors electronics and real-time data processing capabilities.
The ATLAS Liquid Argon (LAr) calorimeter measures the energy of particles produced in LHC collisions. This calorimeter has also trigger capabilities to identify interesting events. In order to enhance the ATLAS detector physics discovery potential, in the blurred environment created by the pileup, an excellent resolution of the deposited energy and an accurate detection of the deposited time is crucial.
The computation of the deposited energy is performed in real-time using dedicated data acquisition electronic boards based on FPGAs. FPGAs are chosen for their capacity to treat large amount of data with very low latency. The computation of the deposited energy is currently done using optimal filtering algorithms that assume a nominal pulse shape of the electronic signal. These filter algorithms are adapted to the ideal situation with very limited pileup and no timing overlap of the electronic pulses in the detector. However, with the increased luminosity and pileup, the performance of the filter algorithms decreases significantly and no further extension nor tuning of these algorithms could recover the lost performance.
The back-end electronic boards for the Phase-II upgrade of the LAr calorimeter will use the next high-end generation of INTEL FPGAs with increased processing power and memory. This is a unique opportunity to develop the necessary tools, enabling the use of more complex algorithms on these boards. We developed several neural networks (NNs) with significant performance improvements with respect to the optimal filtering algorithms. The main challenge is to efficiently implement these NNs into the dedicated data acquisition electronics. Special effort was dedicated to minimising the needed computational power while optimising the NNs architectures.
Five NN algorithms based on CNN, RNN, and LSTM architectures will be presented. The improvement of the energy resolution and the accuracy on the deposited time compared to the legacy filter algorithms, especially for overlapping pulses, will be discussed. The implementation of these networks in firmware will be shown. Two implementation categories in VHDL and Quartus HLS code are considered. The implementation results on Stratix 10 INTEL FPGAs, including the resource usage, the latency, and operation frequency will be reported. Approximations for the firmware implementations, including the use of fixed-point precision arithmetic and lookup tables for activation functions, will be discussed. Implementations including time multiplexing to reduce resource usage will be presented. We will show that two of these NNs implementations are viable solutions that fit the stringent data processing requirements on the latency (O(100ns)) and bandwidth (O(1Tb/s) per FPGA) needed for the ATLAS detector operation.
The talk addresses the use of neural networks in particle tracking applications. Image based approaches (Convolutional neural networks) and pattern based approaches (graph networks) are being discussed that have successfully been used in the TrackML particle tracking challenge.
In modern neural networks, supervised learning is implemented as minimization of a loss function that typically represents an estimate of the prediction error on the training samples.The gradient of the loss function is traversed in steps towards the minimum, and at each step the prediction error is propagated backwards to all the network weights.The gradient steps are computed using the loss on the training data, and the loss on an independent "test" dataset is monitored: the losses on the training and test datasets are then used to assess the tradeoff between optimization and generalization.
In this work, I will review the landscape of loss functions used in modern artificial neural networks, and will present some perspectives for possible improvements, inspired by the functioning of the human brain.
In the collider physics searches, missing values can occur if some of the final state particles are not present in all the events. The electroweak production of the $Z\gamma jj$ – a good probe for the electroweak symmetry breaking – is an example of a process with such final state. Third jet parameters are known to be good at distinguishing it from its’ main background – QCD $Z\gamma jj$ production – but only minor fraction of events has a third jet in the final state. This report uses third jet parameters in the EWK/QCD $Z\gamma jj$ processes separation to study the automated methods for the missing values treatment in the advanced machine learning algorithms. The results are compared with the results obtained with manual clustering and statistical imputation.
Kalliopi Petrou (soprano), accompanied by Elia Sempere (Piano) and Tomaso Dorigo (Flute).
\begin{document}
\title{Overview of Heavy Ion Results at LHCb}
\author{V. ~Pugatch on behalf of the LHCb Collaboration}
\affiliation{Institute for Nuclear Research \ Nat. Acad. of Sci. of Ukraine}
\address{47, Prospekt Nauki, Kyiv, 03680, Ukraine}
\email{pugatch@kinr.kiev.ua}%e-mail
Overview of recent results on heavy ion collisions explored in collider and fixed target mode in the LHCb experiment are presented. Distributions pf physics events over transverse momentum, rapidity and multiplucity for various final state hadrons produced in the forward rapidity were measured at 5.02 and 8.16 TeV in p-p, p-Pb and Pb-Pb collisions. Interpretation of the peculiar features (enhancement, suppression) observed in data for Nuclear Modification Factors and Forward-Backward asymmetries are briefly discussed in frames of selected theoretical models. Prospects of further studies in Run 3 with upgraded LHCb detector will be presented.
\maketitle
\end{document}
In heavy-ion collisions at intermediate energies, nuclear matter will be compressed to densities corresponding to the ones in the core of neutron stars. This opens the opportunity to explore the properties of strongly interacting matter in the laboratory, such as the high-density equation-of-state, which governs the structure of compact stellar objects, and the dynamics of neutron star mergers. Moreover, such experiments are well suited to search for elementary phases of high-density QCD matter, which may feature a chiral phase transition, possibly including mixed phases and a critical endpoint. These fundamental questions will be addressed by future heavy-ion programs at upcoming facilities, such as the Compressed Baryonic Matter (CBM) experiment at FAIR, and the Baryonic Matter at Nuclotron (BM@N) at NICA. Important detector components of these experiments, such as the silicon tracking systems and the forward hadronic calorimeters, are jointly developed by the two collaborations. The BM@N experiment will perform high-precision measurements of hadrons including multi-strange (anti-) hyperons and hypernuclei up to Au-beam energies of 3.8A GeV, while the CBM experiment will in addition study lepton pairs and charmed particles up to Au beam energies of 11A GeV. Most of these particles will be studied for the first time in this energy range. The physics programs and the status of the proposed experiments will be discussed.
The DAMA/LIBRA experiment (about 250 kg of highly radio-pure NaI(Tl)), is running deep underground at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N.; its main aim is the investigation of Dark Matter (DM) particles in the Galactic halo by pursuing the model independent DM annual modulation signature. The results released so far have been obtained with the data of the first phase of measurements (DAMA/LIBRA-phase1) lasted for seven annual cycles with an exposure of 1.04 ton x yr and the data of the second phase (DAMA/LIBRA-phase2), when the energy threshold for the data analysis have been lowered down to 1 keV energy threshold. The first six annual cycles of the DAMA/LIBRA—phase2 data (cumulative exposure 1.13 ton $\times$ yr) have been released in 2018. DAMA/LIBRA data (and the former DAMA/NaI ones) gives for the presence of DM particles in the galactic halo with 12.9$\sigma$ C.L. in the energy region 2-6 keV. No systematic or side reaction able to mimic the exploited DM signature has been found. The obtained DAMA model independent evidence is compatible with a wide set of scenarios regarding the nature of the DM candidate and related astrophysical, nuclear and particle Physics. In the talk, two new annual cycles of DAMA/LIBRA-phase2 data will be presented and the perspectives of the experiment will be addressed.
The possibility of a dark photon in the sub-MeV mass range which has a kinetic mixing with the Standard Model to be a dark matter candidate is highly constrained due to the stringent limits from astrophysical experiments as well as $\Delta N_{\rm eff}$. We present a particle physics model comprising of two hidden sectors where one hidden sector has a direct kinetic mixing with the SM while the second hidden sector couples directly only to the first hidden sector. If the dark photon resides in the second hidden sector, then it can only couple to the SM indirectly via the first hidden sector. We show that this set up can produce a dark photon relic density consistent with experiment as well as escape bounds from astrophysical experiments. We solve the coupled Boltzmann equations and trace the temperature evolution of the sectors involved. We show that the temperature gradient between the sectors allows one to add extra relativistic degrees of freedom without violating bounds on $\Delta N_{\rm eff}$.
The talk is based on arXiv:2103.15769 [hep-ph].
We study collective modes in chirally asymmetric and momentum-anisotropic quark-gluon plasma, using a kinetic theory approach which is valid in the quasi-particle regime. We introduce a general ansatz to describe the parton distribution functions, and decompose the polarization tensor in terms of nine independent components. We derive and solve the dispersion equations. We discuss the dependence of the spectrum on the chiral chemical potential and the parameters that characterise the aniostropy of the distribution function. We study in particular the magnitude and domain of the unstable solutions, which can have an important influence on the system's dynamics.
We calculated four types of vorticities in non-central Au+Au collision at energies $ \sqrt{S_{NN}} $ = 5--200 GeV within the microscopic transport model PACIAE. We find that the initial vorticities show clearly non-monotonic dependence on the collision energies, which is in accordance with a previous study. Our calculation shows that the turning point is around 10-15 GeV for different vorticities.
Abstract:
LHC data on the correlations of the elliptic flow of particles at low and high $p_T$ from Pb+Pb collisions at $√s_{NN}$= 5.02 TeV are analyzed in the framework of the HYDJET++ model. This model includes soft and hard components which allows to describe the region of both low and high transverse momenta. The origin of $v_2$ values in different $p_T$ regions is investigated at different centralities. It is shown that the experimentally observed correlations between $v_2$ at low and high $p_T$ in peripheral lead-lead collisions is due to correlation of particles in jets.
Heavy quarks are mainly produced at the early stages of relativistic heavy-ion collisions before the formation of the quark-gluon plasma (QGP). Heavy quarks then experience the entire evolution of the QGP medium, and thus are ideal probes of the QGP properties. Measuring the open heavy flavor hadrons and their decayed electrons with different observables provides information for different stages of heavy-ion (A+A) collisions, e.g. directed and elliptic flows for the initial conditions and diffusion, nuclear modification factor for the energy loss, and relative yields of various hadrons for the hadronization. Measuring the suppression of heavy quarkonia production in A+A collisions was proposed as an evidence of the QGP formation, and believed to be sensitive to the medium temperature. In p+p collisions, measurement of quarkonia production helps in understanding both the perturbative (hard scattering) and non-perturbative (evolution to the quarkonium bound states) aspects of Quantum Chromodynamics. Additionally, studying the production of heavy flavor hadrons and quarkonia in p(d)+A collisions can be used to quantify the Cold Nuclear Matter effects, which provide critical inputs for interpreting the observed modifications to the heavy flavor production by the QGP.
The STAR Heavy Flavor Tracker, operated from 2014 to 2016, provides excellent track pointing resolution, enabling reconstruction of short lived open heavy flavor hadrons via their hadronic decays. The STAR Muon Telescope Detector operated since 2013 allows reconstruction of heavy quarkonia via dimuon decay channel. In this talk, we will present an overview of recent STAR heavy flavor measurements. We will show results on production of open charm hadrons and electrons from heavy flavor hadron decays in Au+Au collisions. Furthermore, we will report measurements of $J/\psi$ and $\Upsilon$ in p+p, p+Au, and Au+Au collisions, and the $J/\psi$ in jet production in p+p collisions.
The bottomonium states with their different binding energies and radii dissolve at different temperatures of the medium produced in relativistic heavy-ion collisions. Relative yields of bottomonium and their survival in the medium have the potential to map the properties of Quark-Gluon-Plasma (QGP). This is the FIRST study that the rate equations of dissociation and recombination are decoupled and solved separately using the Bateman equation that makes easier the calculation of the net effect of QGP. In this study, we estimate the combined effect of color screening, gluon-induced dissociation and recombination on Bottomonium production in heavy-ion collisions (Pb+Pb ions) at center of mass energy 5.02 TeV. To solve the recombination rate equation, we have used a naive approach of Bateman solution which ensures the dissociation of the recombined bottomonium in the QGP medium and the effects of the correlated mechanism of recombination and the dissociation of newly formed pairs. The modifications of bottomonium states are estimated with help of decoupled equations of gluon dissociation and recombination in an expanding QGP. Such a model study is published in Nucl. Phys. A 1007, 122130 (2021), DOI: 10.1016/j.nuclphysa.2020.122130.
Recent ALICE results on the yield of (multi-)strange particles in pp and p--Pb collisions reveal the possibility that similar strange quark production mechanisms could be present in all collision systems.
The $p_{\rm T}$-dependent baryon-to-meson yield ratio in hadronic and nuclear collisions is sensitive to the collective expansion of the system, the partonic recombination into hadrons, the jet fragmentation and hadronization.
In this contribution, we explore the connection between (multi-)strange hadron yields enhancement and jet production via the measurement of the $p_{\rm T}$-differential spectrum of strange and multi-strange particles (${\rm K}_{\rm S}^{0}$, $\Lambda$ ($\overline{\Lambda}$), $\Xi^{\pm}$ and $\Omega^{\pm}$) within jets and in the underlying event, in pp collisions at $\sqrt{s}=13$ TeV and p--Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV, respectively.
To study physical observables in the HADES experiment, it is extremely important to have
a model that can describe the data well. Recently, the HADES experiment collected
collision data for Au+Au@1.23 AGeV and Ag+Ag@1.58AGeV. One of the important
subsystems of the setup is the forward hodoscope, which measures the spectators charge
(FWALL). The comparisons of the experimental charge distributions measured with the
FWALL with the corresponding charge distributions from the DCM-QGSM-SMM event
generator will be presented.
The existence and location of the QCD critical point is an object of both experimental and theoretical studies. One of the main goals of NA61/SHINE, a fixed-target experiment at the CERN SPS, is the search for the critical point of strongly interacting matter. The comprehensive data collected during a two-dimensional scan in beam momentum (13A-150A GeV/c) and system size (p+p, p+Pb, Be+Be, Ar+Sc, Xe+La, Pb+Pb) allows for a systematic search for the critical point - the search for a non-monotonic dependence of various correlation and fluctuation observables on collision energy and size of colliding nuclei. An example of such observable is local fluctuations of particle densities in transverse momentum space, which can be probed with an intermittency analysis by measuring the scaling behavior of factorial moments of multiplicity distributions.
This contribution will review ongoing NA61/SHINE studies to search for the critical point of strongly interacting matter.
The initial motivation to study d+Au collisions was to study the cold
nuclear matter effects and to use this as a control experiment to better
understand the experimental signatures of Quark Gluon Plasma (QGP) in
heavy ion collisions. From 2013, we have been observing unexpected results
indicating the formation of QGP even in small system collisions.
Suppression in the nuclear modification factor RAA of Pi0 and jets
is observed in the central d+Au collisions, which could be attributed
to formation of QGP droplets but, along with this, the results also
indicate a counter-intuitive enhancement of RAA in peripheral events.
Our aim is to study the question whether the standard way to determine
collision centrality - so successful in case of large systems - is
still valid for small systems, like d+Au or p+Au. Since the QGP, even if formed, is transparent to high pT direct photons from initial hard scatterings, the high-pT photon RAA should be unity and independent of centrality. Furthermore, the ratio of direct photon yields to pi0 yields should exhibit the same centrality dependence as the pi0 RAA. Deviation from these expectations is a strong indication that the centrality definition is biased.
In this talk, I will highlight preliminary results from d+Au collisions
and the status of analysis in p+Au system.
The study of phenomenology of the strong nuclear force (QCD) in High energy collisions of hadrons accessing the data from particle physics colliders is an ongoing research during last two decades. Different phenomenological models along with the event generators are used to reproduce experimental data.
There is confrontation of such model components and experimental data during its validation in a systematic way though these event generators are very useful. To overcome these challenges, the RIVET (Robust Independent Validation of Experiment and Theory) platform has been used during last decade~\cite{Bierlich:2020wms, Bierlich:2019rhm}. The RIVET analysis accounts for the comparisons between data and theoretical calculations of the final state of collision events. A direct comparison could be established between Monte–Carlo event generators and data using RIVET analysis.
We have already studied the production of charged-particles in proton-proton (p-p) and heavy-ion (Pb-Pb) collisions using Angantyr model in PYTHIA8 at LHC energies. In the analysis work, the charged-particle multiplicity has been observed as a function of mid-rapidity $|\eta|$ and transverse momentum $p_{T}$ in p-p collision. In heavy-ion (Pb-Pb) collision, this observable is studied as a function of $p_{T}$ and mean collision centrality ($
STAR’s beam energy scan program at RHIC provides data on net-proton number fluctuations with the goal to detect the QCD critical point and first-order phase transition. Interpreting these experimental signals requires a vital understanding of the interplay of critical phenomena and the nonequilibrium dynamics of the rapidly expanding fireball. We study these aspects with a fluid dynamic expansion coupled to the explicit propagation of the chiral order parameter sigma via a Langevin equation. Assuming a sigma-proton coupling through an effective proton mass, we relate cumulants of the order parameter and the net-proton number at freeze-out and obtain observable cumulant ratios as a function of beam energy. We emphasize the role of the nonequilibrium first-order phase transition twofold: First, the presence of an unstable phase causes the well-known bending of the trajectories in the space of temperature and baryochemical potential. For these cases at lower beam energies, the system crosses the freeze-out line more than once, allowing us to calculate a wide range of cumulants for each initial condition. Second, the thermodynamic susceptibilities diverge along the spinodal lines in nonequilibrium. Depending on the freeze-out parameters, these divergences can have a dramatic impact on the calculated cumulants and cumulant ratios.
The CMS experiment uses a two-level triggering system consisting of the Level-1, instrumented by custom-design hardware boards and delivering an output rate of 100 kHz, and the High Level Trigger, a streamlined version of the offline reconstruction software running on a computer farm, which sends a rate of about 1 kHz to permanent storage. This system has been evolving continuously since the startup of the LHC. While the current system will basically remain in use for the next LHC running period (Run-3 starting in 2022), new features and algorithms are already being developed to take care of higher data loads due to increasing LHC luminosity and pileup but also of new experimental signatures to be investigated (in particular, displaced decay vertices stemming from relatively long-lived particles created in proton-proton collisions). A major upgrade of the triggering system will then happen within the framework of the upgrade of the collider to the High-Luminosity LHC, which will deliver a luminosity of 5-7.5 times the design value, corresponding to 140-200 pileup events. An important difference from the present system will be the fact that after the upgrade, information from the silicon strip tracker will be available already for the Level-1 Trigger. This will allow CMS to use so-called particle flow objects, i.e. signals seen not only in one subdetector but put together from all available subdetectors, resulting in much sharper efficiency turn-on curves for trigger objects. Also, trigger rates will rise by a factor of about 7.5 both at Level-1 (to 750 kHz) and at the High-Level Trigger (7.5 kHz) and the latency - the processing time available for arriving at the Level-1 trigger decision - will increase significantly, allowing for the use of more sophisticated algorithms at Level-1.
The MUonE experiment aims at an independent and competitive determination of the leading hadronic contribution to the muon anomalous magnetic moment $a_\mu = (g_\mu-2)/2$, based on an alternative method, complementary to the existing ones. It could have a crucial role to clarify the comparison of the $a_\mu$ measurement with the Standard Model, given the recent Fermilab result, and the tension between the accepted theory prediction and a new Lattice QCD calculation.
MUonE proposes to measure the hadronic component of the running electromagnetic coupling by the $\mu e$ elastic scattering obtained by the 160 GeV muon beam at CERN on fixed target. The project status will be presented, in view of the test run on a reduced detector expected in 2021-22.
Antihydrogen experiments hosted at CERN's Antiproton Decelerator rely on charge exchange [1] or three body recombination [2] formation mechanisms. In both cases, the anti-atoms are produced in a wide range of highly excited Rydberg states preventing the atoms' extraction through Stark acceleration or magnetic focusing into a field-free environment and consequently hindering spectroscopy or gravity measurements in a beam. I will discuss novel approaches to enhance the decay of the initially formed Rydberg levels toward the ground state. Mixing states either via crossed electric and magnetic fields [3] or impinging THz and/or microwave light [4] allows to efficiently employ deexcitation lasers and achieve close to unity ground state fractions in a few tens of microseconds which is compatible with experimental requirements. Results of a technology demonstration of cesium Rydberg state mixing with THz photomixing [5] will be discussed in the context of antihydrogen deexcitation. Finally, developments of a Rydberg hydrogen beam for a proof-of-principle experiment will be presented.
[1] Amsler, C., Antonello, M. et al. Pulsed production of antihydrogen, Commun. Phy. 4, 19 (2021)
[2] Kuroda, N., Ulmer, S., Murtagh, D. et al. A source of antihydrogen for in-flight hyperfine spectroscopy, Nat Commun 5, 3089 (2014)
[3] D. Comparat and C. Malbrunot. Stimulated decay and formation of antihydrogen atoms, Phys. Rev. A 99, 013418 (2019)
[4] T. Wolz, C. Malbrunot, M. Vieille-Grosjean, and D. Comparat. Stimulated decay and formation of antihydrogen atoms, Phys. Rev. A 101, 043412 (2020)
[5] M. Vieille-Grosjean, E. Dimova, Z. Mazzotta, D. Comparat, T. Wolz and C. Malbrunot. Induced THz transitions in Rydberg caesium atoms for application in antihydrogen experiments, Eur. Phys. J. D 75:27 (2021)
We discuss here recent results on $e^+ e^−$ annihilation to hadrons below 2 GeV obtained with the SND detector at the VEPP-2000 collider. Among others we report cross sections and dynamics properties for the $e^+ e^- \to \pi^+ \pi^-$, $e^+ e^- \to n \bar{n}$, $e^+ e^- \to \eta \pi^0 \gamma$, and $e^+ e^- \to \eta \eta \gamma$ processes.
The recent revolution of lasers with increased power and shorter pulse length opens new possibilities for fusion for energy. Two ideas are taken from recent research. One is from high energy heavy ion research, that Quark Gluon Plasma (QGP) may burn (hadronize) simultaneously, i.e. across a hyper-surface with time-like normal, without Rayleigh-Taylor instabilities. The other new idea comes from nano-technology, that nano-antennas embedded in the target, may modify the laser light absorption in a way that this simultaneous ignition can be achieved. The experimental verification of these ideas are in progress at the Wigner R.C.P. at lower, mJ, energies. Amplification of laser light absorption is already verified. The verification of simultaneous transition in the whole volume is coming soon. Expectedly in November s Fall near 30 J short pulse laser will become available at ELI-APLS in Szeged, Hungary.
ABSTRACT
The combination of different technologies opens always new gates. One of such possibilities seems to be the exploitation of nanotechnologies in general and nanoplasmonics in particular to laser inertial fusion. This presentation describes some unique properties of propagating and localized surface plasmons, including those, excited by high laser fields, and presents some of their positive influence on nuclear processes, including fusion of light nuclei. Illustrative examples of the preliminary experimental results are also described.
Femtosecond laser irradiation induced structural changes and their dependence on the plasmonic effect of embedded gold nanoparticles were investigated in urethane dimethacrylate (UDMA) polymer.
The UDMA polymers with and without nanoparticles were exposed to femtosecond laser irradiation with different energy. The morphology of the surface of the treated spot and its environment were studied by white light interferometry and the structural changes were investigated by Raman spectroscopy. The presence of the plasmonic nanoparticles resulted in more remarkable changes in the bonding-structure of the polymer.
The correction to the Coulomb energy due to virtual production of e+e- pairs, which is on the order of one percent of the Coulomb energy at nuclear scales is discussed. The effects of including a pair-production term in the semi-empirical mass formula and the correction to the Coulomb barrier for a handful of nuclear collisions using the Bass and Coulomb potentials are studied. With an eye toward future work using Constrained Molecular Dynamics (CoMD) model, we also calculate the correction to the Coulomb energy and force between protons after folding with a Gaussian spatial distribution. Currently, we are working to find e+e- production rates in ion collisions by solving the Dirac equation coupled to the Coulomb trajectory of two ions. In particular, we are studying the effect of pair production on fusion cross-sections.
Recently Nanoplasmonic Laser Induced Fusion Experiments were proposed, as an improvement in achieving laser driven fusion [1]. This combines recent discoveries in heavy-ion collisions and optics. The existence of detonations with time-like normal on space-time hyper-surfaces combined with absorption adjustment using nanoantennas allows the possibility of heating the target in an opposing laser beam setup [2]. Here we will present particle-in-cell model of such colliding beam setups, also showing a kinetic model of resonant nanoantennas using the capabiliteis of the EPOCH multi-component PIC code[3].
[1] L.P. Csernai, N. Kroó, & I. Papp, Radiation-Dominated Implosion with
Nano-Plasmonics, Laser and Particle Beams 36, 171-178 (2018).
[2] L.P. Csernai, M. Csete, I.N. Mishustin, A. Motornenko, I. Papp, L.M.
Satarov, H. Stöcker & N. Kroó, Radiation-Dominated Implosion with Flat
Target, Physics and Wave Phenomena, 28 (3) 187-199 (2020) in press,
accepted February 3, 2020, (arXiv:1903.10896v3).
[3] T. D. Arber, et. al. Contemporary particle-in-cell approach to laser-plasma
modelling Plasma Phys. Control. Fusion 57, 113001 (2015)
The Relativistic Heavy Ion Collider (RHIC) is the world’s only polarized proton collider, capable of reaching center of mass energies up to 510 GeV. The STAR experiment has been carrying out a cold QCD program, to gain deeper insight into the spin structure and dynamics of the proton. The collection of longitudinally polarized data concluded in 2015. One of the goals of this data is to study the gluon helicity distribution function (∆g($x$)), by measuring the longitudinal double-spin asymmetry (A$_{LL}$) of jets. Measurements were taken at √s = 200 GeV and 510 GeV with different topological configurations in pseudorapidity (η), to maximize the kinematic coverage in momentum fraction ($x$) down to ~0.01 and to better constrain the shape of ∆g($x$). On the other side, the transversely polarized proton collisions at RHIC enable the studies of the transverse spin structure, such as the transversity and Sivers distributions, as well as polarized fragmentation functions. These studies can be used to test universality, and given STAR’s wide kinematic range, also aid in constraining transverse momentum dependent evolution effects. In this talk, we present the recent STAR measurements for longitudinal and transverse polarization, besides selected unpolarized results. STAR is currently installing a suite of new sub-detectors in the forward region (2.5 < η < 4). How those upgrades will supplement previous STAR measurements will also be briefly discussed.
Numerous potential models are used to calculates the various properties of the given quarkonium system in high energy physics. The investigation of quarkonium systems is widely studied by using the solution of the second order differential equation. Various methods to solve the second-order differential equation such as Schrodinger equation, Dirac equation and Klein-Gordon equation with different potentials. These methods are Nikiforov-Uvarov(NU) method, supersymmetric quantum mechanics(SUSYQM), factorization method, formula method, asymptotic iteration method (AIM), ansatz method, exact quantization rule etc. We proposed linear plus modified Yukawa potential model (LIMYP) and D- dimensional radial Schrodinger equation for LIMP have been obtained via the generalized Nikiforov-Uvarov (NU) method. The energy eigenvalues and wave function are obtained in the D- dimensional space. The LIMYP is combination of the two potential, the linear potential and modified Yukawa potential as
\begin{equation}
V(r)=A_{1} r+ \frac{A_{2} e^{-\alpha r}}{r}-\frac{A_{3} e^{-2 \alpha r}}{r^2}+A_{4}
\end{equation}
The properties of bottomonium and charmonium mesons also have been calculated. Our calculated results are in good agreement with experimental data and other theoretical studies.
Search for a two nucleon system or the dineutron (n2) as a bound particle or the two nucleon nuclei without protons was raised for a first time in 1946 [1]. In this publication, the possibility to generate mono energy neutrons as well as the dineutron in the d-t nuclear reaction was considered. Since that time until nowadays the dineutron was the subject to hunt in nuclear reactions on light nuclei. In the same time, according to the Pauli principle the two neutrons, composing such exclusive quantum system as the dineutron, are allowed to exist with antiparallel spins or in a singlet state only. Wherein, taking into account charge independence (isotopic invariance) of nuclear forces and our knowledge about a singlet state of the deuteron, one can unambiguously affirm that such a singlet state of the dineutron is unbound by definition. Therefore, during last years main efforts were targeted at dineutron search in nuclear reactions on nuclei, located far from beta-stability valley, characterized by neutron excess and possessing the neutron halo or the neutron skin. This direction in nuclear physics is entitled as the dineutron correlations.
In 1972 A.Migdal published a paper [2], where the formation of the dineutron in a bound state was predicted following to escape of the two paired up neutrons from compound nucleus. It is worth noting that this correlated escape can take place for the case when the kinetic energy of the two neutrons is much less of their interaction energy and if single particle levels are formed within the potential well of the heavy nucleus but beyond its radius. Finally, in [2] a theoretical justification has been presented in support of existence of such levels in the energy range [0-0.4] MeV to bind the two neutrons in one particle known as the dineutron.
In our study of nuclear reactions with neutrons adsorption by 159Tb nuclei, we observed one more nuclear reaction channel, namely: 159Tb(n,n2)158gTb. The main features of this nuclear reaction channel were the detection of gamma-rays due to decay of 158gTb nuclei in ground state, and buildup of such nuclei for 6.85 MeV energy impinging neutrons, what is 1.3 MeV below the threshold energy of the corresponding 159Tb(n,2n)158gTb nuclear reaction. Main results of this study were published in [3]. The only drawback of this experiment was the statistical significance of our results below 5σ. An additional argument in support of dineutron existence hypothesis would be observation of a bound dineutron in a corresponding nuclear reaction on another heavy nucleus.
In this work we present the results of dineutron formation in the 197Au(n, n2)196gAu nuclear reaction. The golden foils of 0.999 grade were irradiated with d-D neutrons at MGC-20E cyclotron at MTA Atomki, Debrecen, Hungary. The energy of impinging neutrons was ~ 2 MeV below the threshold energy of the 197Au(n,2n)196gAu nuclear reaction, which equals 8.11 МеV. Results of bound dineutron detection are presented below. The statistical significance of 355.7 keV gamma peak areas exceeded 5σ. We also conducted a very thorough analysis of all possible systematic uncertainty contributors. Therefore, the existence of a bound dineutron was proved in our paper [4], and the only possible disintegration mode of such absolute neutron exceed nucleus is a beta-minus decay with the formation of the deuteron.
We used 355.684 keV gamma line to determine cross-sections for 197Au (n,n2)196gAu nuclear reaction. Thus, for deuteron energy 3.459 MeV, minimal neutron energy 6.09 MeV, average neutron energy 6.19 MeV and maximal neutron energy 6.39 MeV reaction cross-section was 180±60 μb based on 9.4 σ statistical significance of gamma-peak. For deuteron energy 3.523 MeV, minimal neutron energy 6.175 MeV, average neutron energy 6.275 MeV and maximal neutron energy 6.455 MeV reaction cross-section was 37±8 μb based on 6.4 σ statistical significance of gamma-peak.
Beside the induced activity of 158gTb in the instrumental gamma-ray spectra of irradiated Tb sample, we also observed gamma-peaks due to de-excitation of 160Dy because of beta-minus decay of 160Tb into 160Dy. In the beginning these gamma-peaks were mainly from the 159Tb(n,γ)160Tb nuclear reaction, later - from the nuclear fusion reaction 158Gd(d,γ)160Tb, or directly from the 158Tb(d,γ)160Dy fusion reaction [5,6]. Based on results of 160Tb/160Dy induced activity measurements during 2.5 years after neutron irradiation complete, the half-year of such system was determined as 123 ±24 d rather than 72.3 d reference value.
We also have developed the mathematical model to describe nuclear processes of low energy nuclear fusion for 158Gd or 158Tb with the deuteron at room temperature conditions. This allowed us to calculate a modified half-life for such nuclear system under simultaneous fusion and decay. Our result of calculation equals 126.8 d and found to be in a very good agreement with experimental value.
Therefore, in our work we demonstrated that generation of bound dineutrons along with heavy nuclei in the output channel of neutron-induced nuclear reactions does not only represent a new nuclear reaction type and channel, but also provides prerequisites for fusion between heavy and light nuclei at room temperature conditions and affects half-lives of nuclear reaction products. These our results represent new frontiers in low energy nuclear physics.
[1] M.Y.Colby, R.N.Little, Phys. Rev. 70, 437 (1946).
[2] A.B. Migdal, Yad. Fiz. 16, 427 (1972) / Sov. J. Nucl. Phys. 16, 238 (1973).
[3] I.Kadenko, Europhys. Lett. 114, 42001 (2016).
[4] I.Kadenko et al, Europhys. Lett. 131, 52001 (2020).
[5] I.Kadenko, N.Sakhno, Nucl. Phys. A 994, 1231660 (2020).
[6] I.Kadenko, N.Sakhno, Acta Phys. Pol. B 83 No.1, Vol.51 (2020).
We will present results on Spin Density Matrix Elements (SDMEs) measured in hard exclusive muoproduction of $\rho ^0$ and $\omega $ mesons on the proton at COMPASS using 160 GeV/$c$ polarised $\mu ^{+}$ and $\mu^{-}$ beams scattering off a liquid hydrogen target. The measurements cover the range 5 GeV/$c^2$ $< W <$ 17 GeV/$c^2$, 1.0 (GeV/$c$)$^2$ $< Q^2 <$ 10.0 (GeV/$c$)$^2$ and 0.01 (GeV/$c$)$^2$ $< p_T^2 <$ 0.5 (GeV/$c$)$^2$. Here, $Q^2$ denotes the virtuality of the exchanged photon, $W$ the mass of the final hadronic system and $p_T$ the transverse momentum of the vector meson with respect to the virtual-photon direction. The measured non-zero SDME values for transitions of transversely polarised virtual photons to longitudinally polarised vector mesons ($\gamma _{T} \rightarrow V_{L}$) indicate a violation of $s$-channel helicity conservation. Additionally, for $\rho ^0$ production we observe a dominant contribution of natural-parity-exchange transitions and a small contribution of unnatural-parity-exchange transitions. On the contrary, the contribution of unnatural-parity-exchange for $\omega $ production is significant and it decreases with increasing $W$, being still non-negligible at the largest $W$ values accessible at COMPASS.
The results provide an important input for modelling Generalised Parton Distributions (GPDs). In particular, they may allow to evaluate in a model-dependent way the role of parton-helicity flip GPDs ("transversity GPDs") in exclusive vector meson production.
The Standard Model of particle physics is an incomplete theory and it seems to be an approximation of a deeper and more fundamental theory. The idea that might lead to a better understanding of the universe is that the quarks and leptons, which are now treated as point-like particles are composite in nature having underlying substructure and made up of even smaller particles bound together with some force. This force must be very strong. The underlying substructure implies the existence of stable excited states, which will have higher energy and can decay into lower-energy states. The existence of excited states is a natural consequence of composite models for quarks and leptons. Compositeness models predict the existence of excited states of quarks and leptons at this characteristic scale of the new binding interaction. Considerable efforts have been expended into the search of excited leptons by various collaborations including at the LHC and limits have been set on the masses and coupling of excited leptons.
Keywords: Standard Model, leptons, quarks, excited, Compositeness, LHC.
The NA62 experiment at CERN reports new results from studies of radiative kaon decays K+ ➔ e+ vg (Ke2g) and K+ ➔ pi0e+vg (Ke3g), using a data sample recorded in 2017-2018. The sample comprises O(10k) Ke2g candidates and O(100k) Ke3g candidates with sub-percent background contaminations. Preliminary results with the most precise measurement of the and branching ratios, determination of structure-dependent Ke2g form factors, and T-asymmetry measurement in the Ke3g decay, are presented.
Recent results from the ATLAS experiment on the charmonium production, Bc production and decays, and exotic heavy hadrons will be presented. The measurement of J/psi and psi(2S) differential cross sections at large transverse momentum values in proton-proton collisions at 13 TeV will be reported. The measurement of the ratios of the Bc+ and B+ production cross sections in proton-proton collisions at 8 TeV will be discussed. New results on the Bc decays to J/psi Ds(*) final states obtained with the whole Run 2 data at 13 TeV will be shown. Studies of the Pentaquarks with hidden charm in the Lambda_b decays in proton-proton collisions at 7 - 8 TeV will also be reported.
We present a study of the average transverse momentum and multiplicity distributions using different Monte Carlo event generators. The sensitivity in these observables to the collective phenomena at the LHC and NICA energies is investigated. Besides, we explore the average transverse momentum as a function of the multiplicity scaled to the transverse collision area, the energy, and entropy densities to scan for a possible phase transition. The results and predictions from PYTHIA, EPOS, and UrQMD, show a sudden change in the energy and entropy with slight discrepancies among data and simulated data, suggesting a possible transition phase.
Going beyond the simplified gluonic cascades, we have introduced both gluon and quark degrees of freedom for partonic cascades inside the medium. We then solve the set of coupled evolution equations with splitting kernels calculated for static, exponentially expanding and Bjorken media to arrive at medium-modified parton spectra for quark and gluon initiated jets. For our calculations, we have included phenomenologically driven parton fractions for the calculation of inclusive jet $R_{AA}$ and its rapidity dependence. Finally, we have studied the path-length dependence of jet quenching for different types of expanding media by calculating the jet $v_{2}$. These studies help to quantify a discriminating power of different observables for distinguishing the type of the medium expansion.
The search for the expected first-order phase transition between the hadronic matter and quark-gluon plasma and the corresponding critical endpoint is an active field of research. One of the main approaches to study this problem is based on fluctuations of e.g. net-baryon number, net-charge, or net-strangeness number measured in relativistic heavy-ion collisions. The cumulants are commonly used to quantify such fluctuations and correlations. However, the factorial cumulants are easier to interpret since they represent the integrated genuine multi-particle correlation functions. It is important to study the correlations originating from effects other than those related to the first-order phase transition. In this talk, the proton, antiproton, and mixed proton-antiproton factorial cumulants originating from the global baryon number conservation will be presented. Our results can be tested experimentally.
Conventional Boltzmann transport equation (BTE) has an exponential stationary solution. While studying the equilibrium distribution of the heavy quarks in the quark-gluon plasma using the Fokker-Planck equation (obtained from the conventional BTE), Rafelski and Walton in 2000 showed that this distribution is rather power-like. However, there exists a generalized Boltzmann transport equation whose stationary solution is represented by the Tsallis power-law distribution, and it is possible to approximate this equation in different ways. One such approximation is the relaxation time approximation. Here we propose an approximate iterative analytical solution of the generalized Boltzmann transport equation and indicate some possible applications.
The current work is used to explore the structure of hot and dense system quark gluon plasma (QGP) in order to deal with the dynamics of quarks and gluons in magnetized field. Since a huge and intense magnetic field is expected to be produce at RHIC and LHC, we calculate the equation of states (EoS) in the presence of time dependent magnetic fields with the medium effects of quarks and gluons as quasiparticles. Using quasiparticle model, some important features are noticed which depend on the scales like effective quark mass, temperature and time dependent/independent magnetic field. The model results found that the behaviour of thermodynamic observables influence effectively in the presence of time varying magnetic fields. Therefore the output seems to be significant in the magnetized QGP. The results are compared with earlier results. Interestingly, a new finding results can not be ignored for the study of the evolution of magnetized QGP. The current study could be useful in explaining the physical structure of QGP with the time dependent magnetic field.
The generation of laser pulses with few-fs duration represents a major technological challenge due to the high spectral bandwidth of ultrashort laser pulses. When the pulse duration becomes comparable to the optical cycle of the laser radiation, a spectrum with typically several hundreds of nm width has to be managed with a proper behaviour of the spectral phase. This issue is even more challenging for high-intensity femtosecond lasers, e.g. those used in some laser fusion approaches. In this talk, I will review state-of-the-art femtosecond pulse compression techniques.
The studies of laser-plasma interactions are entering a new regime where the physics of relativistic plasmas is strongly affected by strong-field quantum electrodynamics processes, including hard photon emission and electron-positron pair production. This coupling of quantum emission processes and relativistic collective particle dynamics can result in dramatically new plasma physics phenomena, such as the generation of dense electron-positron pair plasma from near vacuum, complete laser energy absorption or the stopping of an ultra-relativistic electron beam. It is understood that the magnitude of all these phenomena depends on the electromagnetic field configuration. The collision of several phase-matched laser pulses has been identified theoretically as a way to maximize the strength of optical electromagnetic fields achievable at high-intensity laser facilities. This has paved the way for several experimental proposals aimed at both fundamental studies of matter at extreme conditions and the creation of particle and radiation sources. We report here on a systematic analysis of different regimes and opportunities achievable with the concept of multiple colliding laser pulses, for both current and upcoming laser facilities. Several distinct regimes are revealed to be within reach of multi-petawatt laser facilities.
A systematic program of investigations of nuclear reactions in laser-produced plasmas is addressed. Such reactions provide an important diagnostic tool for probing the dynamics and thermodynamics in the plasma and understanding laser ion acceleration and neutron production mechanisms. The goal will be to reach the level of knowledge that allows the measurement of fundamental nuclear cross-sections at low and high particle densities. The quantitative measurement of fusion probabilities in hot and dense plasmas will contribute significantly to our comprehension of stellar composition and evolution and will provide important information for development of fusion energy production and applications such as medical isotope production and compact neutron source development. All of these are some of the main goals of the European Extreme Light Infrastructure (ELI), the Shanghai Superintense Ultrafast Laser Facility, and the Station of Extreme Light in China and similar projects in other countries. In this talk I will discuss (depending on allocated time) results obtained at the ABC-Enea, Texas PW and the Shangai laser Facilities and a preview for the future experiment (2022) at the Vega laser facility in Spain.
It is shown that the convective instability in electron fluids in 3D and 2D Dirac semimetals is strongly inhibited. The major obstacles for the convection are the effects of the Coulomb forces and the momentum relaxation related to the interaction with impurities and phonons. The effect of the Coulomb forces is less pronounced in 2D materials, such as graphene. However, momentum relaxation still noticeably inhibits convection making it very difficult to achieve in practice.
Application of Hybrid Monte Carlo (HMC) technique allowed us to perform the simulations of electronic properties of suspended graphene at as large as $102\times102$ lattices to directly observe the infrared renormalization of the Fermi Velocity for the first time in non-perturbative Quantum Monte Carlo calculations. We compared the results with experiment, and demonstrated the agreement in the specific case, when short-range electron-electron interactions are taken from cRPA approximation. Comparison of HMC data with perturbative calculations made within the Lattice Perturbation Theory (LPT) and in continuum QED demonstrates the importance of lattice-scale physics for the quantitative description of the Fermi Velocity renormalization. Higher-order corrections beyond RPA level are also important, especially in comparison with one-loop and RPA level LPT results, both at zero and finite temperature.
Many theories beyond the Standard Model (BSM) predict new phenomena accessible by the LHC which prevent for example the need of fine-tuning of the Higgs Boson mass, expand the gauge sectors of the SM or explore the dark sector through possible long lived particle decays. Searches for new physics models are performed using the ATLAS experiment at the LHC focusing on exotic signatures that can be realized in serval BSM theories. The results reported do not touch on Dark Matter signatures and use the pp collision data sample collected in Run 2 by the ATLAS detector at the LHC with a centre-of-mass energy of 13 TeV.
Belle II at the electron-positron collider SuperKEKB is the
successor to the Belle experiment. Its design luminosity is 6 · 1035/(cm2s),
40 times the record achieved at KEKB/Belle, at the same center of mass
energy in the bottomonium region. Over the next years it is expected to
accumulate an integrated luminosity of 50 ab−1, collecting by far the
largest sample of B-mesons at electron-positron colliders, together with
large numbers of bottomonium and lighter particles. After a
commissioning run in 2018 the detector started routine data taking in March 2019.
we have collected more than 200 fb-1 statistics so far. In this talk the
current status of the detector, current and future running conditions a
selection of the present physics results and further physics prospects
will be shown.
At RHIC energies, charm quarks are primarily produced in hard partonic scatterings at early stages of ultra-relativistic heavy-ion collisions. This makes them an ideal probe of the Quark-Gluon Plasma (QGP), as they experience the entire evolution of this hot and dense medium. STAR is able to measure the production of charm quarks and their interaction with the QGP through direct reconstruction of hadronic decays of D$^\pm$, D$^0$, D$_\textrm{s}$, and $\Lambda_\textrm{c}^\pm$ hadrons, enabled by the excellent track pointing resolution provided by the Heavy Flavor Tracker.
In this talk, we will present the most recent results on open charm hadron production from the STAR experiment. In particular, we will discuss the nuclear modification factors of D$^\pm$ and D$^0$ mesons which provide information on the charm quark energy loss in the QGP. We will also present the D$_\textrm{s}$/D$^0$ and $\Lambda_\textrm{c}^\pm$/D$^0$ yield ratios as functions of transverse momentum and collision centrality which help us better understand the charm quark hadronization process in heavy-ion collisions. The spectra of D$^0$, D$^\pm$, D$_\mathrm{s}$, and $\Lambda_\mathrm{c}^\pm$ in 10-40$\%$ central Au+Au collisions are used to calculate total charm quark production cross section in Au+Au collisions which, compared to the value measured in p+p collisions, gives insight into charm quark production in heavy-ion collisions.
Phase structure of quark matter with chiral and isospin imbalance is considered in the framework of effective models. There has been considered as two color as well as three color QCD. It was shown that chiral imbalance has several rather peculiar properties such as being universal catalyzer, i. e. it catalyzes all the considered symmetry breaking patterns in the system, including the diquark condensation phenomenon (color superconductivity). Duality properties found earlier have been considered in this case.
Part of the talk is based on
Eur.Phys.J.C 80 (2020) 10, 995 arXiv:2005.05488 [hep-ph]
JHEP 06 (2020) 148 arXiv:2003.10562 [hep-ph]
Phys.Rev. D100 (2019) no.3, 034009 arXiv: 1904.07151 [hep-ph]
JHEP 1906 (2019) 006 arXiv:1901.02855 [hep-ph]
Eur.Phys.J. C79 (2019) no.2, 151, arXiv:1812.00772 [hep-ph]
In this work, we study the non-extensive Tsallis statistics and its applications to QCD and high energy physics. In particular, we present recent investigations on the power-law distributions arising in high energy physics experiments focusing on a thermodynamic description of the system formed, based on Tsallis statistics which could explain this power-law behavior. The possible connections of this statistics with a fractal description of hadrons is also analyzed. Finally, it is discussed the applications of Tsallis statistics in QCD thermodynamics and the equation of state, as well as some implications for Bose-Einstein condensation. This work is based on Refs. [1,2,3,4].
References
[1] E. Megias, V.S. Timoteo, A. Gammal, A. Deppman, ”Bose-Einstein condensation and non-extensive statistics”, eprint arXiv:2105.07548.
[2] A. Deppman, E. Megias, D.P.Menezes, ”Fractals, nonextensive statistics, and QCD”, PRD101 (2020) 3, 034019.
[3] E. Andrade, A. Deppman, E. Meg ́ıas, D.P. Menezes, T. Nunes da Silva, ”Bag-type model with fractal structure”, PRD101 (2020) 5, 054022.
[4] A. Deppman, E. Megias, D.P. Menezes, ”Fractal structures of Yang-Mills fields and non extensive statistics: applications to high energy physics”, MDPI Physics 2 (2020) 3, 455-480.
In the next years the BM@N experiment at the Nuclotron at JINR in Dubna will carry out the physics program with heavy ion beams with energies up to 3.8 AGeV and intensities up to $2$$\cdot$$10^6$ ions/s. The experiment is devoted to measure observables sensitive to the equation of state of dense baryonic matter. To meet this goal the existing BM@N set-up will be upgraded with fast hybrid tracking system, which includes beam tracking detectors, a large aperture silicon tracking system, GEM stations and cathode strip chambers. The measurement of the event plane and centrality will be achieved with a forward hadron calorimeter and granular hodoscopes. The physics program and configuration of the upgraded BM@N set-up will be presented.
The magnetic field and medium effects on electrical and hall conductivities of a hot and magnetized pion gas has been studied. The conductivities has been evaluated using kinetic theory approach in the ambit of relaxation time approximation. Thermal field theoretical techniques has been used to evaluate the dynamical input to these conductivities.
We introduce sequential analysis in quantum information processing, by focusing on the fundamental task of quantum hypothesis testing. In particular, our goal is to discriminate between two arbitrary quantum states with a prescribed error threshold ε when copies of the states can be required on demand. We obtain ultimate lower bounds on the average number of copies needed to accomplish the task. We give a block-sampling strategy that allows us to achieve the lower bound for some classes of states. The bound is optimal in both the symmetric as well as the asymmetric setting in the sense that it requires the least mean number of copies out of all other procedures, including the ones that fix the number of copies ahead of time. For qubit states we derive explicit expressions for the minimum average number of copies and show that a sequential strategy based on fixed local measurements outperforms the best collective measurement on a predetermined number of copies. Whereas for general states the number of copies increases as log 1/ε, for pure states sequential strategies require a finite average number of samples even in the case of perfect discrimination, i.e.,
ε=0.
The work is dedicated to the experimental study of Compton scattering of entangled and decoherent annihilation gammas. The pairs of entangled annihilation photons are produced in electron-positron annihilation. The polarization state of each gamma in such a pair is indefinite. However, the relative polarizations of the photons are orthogonal. After interacting with matter, the initially entangled state of the photons becomes decoherent. And both gammas have the definite polarizations. Since Compton scattering depends on the polarization of photons, the scattering kinematics of entangled and decoherent photons can be quite different. We present the experimental setup for measuring Compton scattering of entangled and decoherent annihilation photons in different states of polarization. The first results on the angular correlations of scattered photons are also discussed.
We investigate the spatial correlations between quantum fields in two regions of space separated by a movable reflecting wall. Our system consists of two cavities separated by a movable reflecting mirror, that is bound to its average position by a harmonic potential. The two semi-spaces are occupied by a quantum massless scalar field, and the mirror acts as a moving boundary condition for the two scalar fields confined in the two cavities. In our approach, both the fields and the mirror are treated quantum-mechanically, and an effective interaction between the field modes in each semi-space, mediated by the reflecting wall, is present.
Using the time-independent perturbation theory in the effective field-mirror interaction, we first evaluate the vacuum spatial correlations between the field operators in the two semi-spaces and show that such correlations are zero. In contrast, correlations between the squared fields in the two cavities in the vacuum state give a nonvanishing term at the second order in the field-mirror effective coupling. This nonvanishing correlation indicates a mutual influence of the field fluctuations in the two cavities mediated by the movable reflecting wall. We also discuss the case of two infinite half-spaces separated by a single movable wall, obtained in the continuous limit when the fixed walls of the two cavities go to infinity, and evaluate the field correlation function on the opposite sides of the moving mirror. We show that the moving mirror gives rise to anticorrelations between the fields in the two semi-spaces and study the dependence of these spatial correlations as a function of the average distance from the moving wall. The observability of these effects is also discussed.
The two-atom interferometer introduces two different yet indistinguishable alternatives for randomly paired atoms to create a joint atom-detection event. The superposition of two-atom amplitudes yields two-atom interference with peculiar features which outshine the classic atom interferometer: (1) two-atom interference is still observable when the time delay of the interferometer is greater than the coherence time of the atom beam and (2) two-atom interference may eliminate phase noises, including background, variation, turbulence, and Raman laser induced phase noises, thereby allowing for higher sensitivity and stability sensing than is achievable by classic atom interferometers. These features are crucial in high sensitivity-accuracy acceleration and rotation measurements. The presented concept and mechanism of two-atom interference can be adapted to other matter-wave interferometers, such as two-neutron interferometer and two-electron interferometer.
We discuss dense cool QCD where a region with spatially inhomogeneous condensate might emerge. In that case, QCD phase diagram may exhibit a Lifshitz regime, which can appear either instead of, or in addition to Critical End Point. We study the Lifshitz regime using a combination of large-N expansion and numerical lattice simulations of an effective O(N) sigma model. We find evidence that quantum fluctuations disorder inhomogeneous condensate ("chiral spirals") and give rise to unusual quantum spin-liquid phase. We also discuss how this novel phase can be detected experimentally.
The continuation of high energy QCD Lipatov's effective action to Euclidean space is performed. The resulting Euclidean QCD RFT action
is considered separately in Euclidean "light-cone" coordinates and axial gauge suitable for the numerical and analytical calculations correspondingly.
The further application of the obtained results is also discussed.
We discuss anomalous fractional quantum Hall effect that exists without external magnetic field. We propose that excitations in such systems may be described effectively by non-interacting parti- cles with the Hamiltonians defined on the Brillouin zone with a branch cut. Hall conductivity of such a system is expressed through the one-particle Green function. We demonstrate that for the Hamiltonians of the proposed type this expression takes fractional values times Klitzing constant. Possible relation of the proposed construction with degeneracy of ground state is discussed as well.
Using numerical first-principle lattice simulations, we show that the vacuum of the electroweak sector of the Standard Model experiences two consecutive (phase) transitions in the background magnetic field at zero temperature. The first transition is associated with the dynamics of both Higgs and vector bosons, while the second transition marks the electroweak symmetry restoration. Our simulations indicate that the new intermediate phase is a liquid of quasiclassical vortices which carry condensates of the charged W bosons in their cores and therefore possess superconducting properties. The transitions appear at the field strengths of the order of 10^20 Tesla.
Hall conductivity topology using the magnetic Brillouin zone procedure
Understanding QCD phase structure is one of ultimate goals of high-energy heavy-ion colliding experiments.
At BNL-RHIC, the Beam Energy Scan (BES-I) program was carried out from 2010 to 2017.
Data sets of Au+Au collisions were collected for various collision energies
from $\sqrt{s_{\rm NN}}=200$ GeV down to $7.7$ GeV by the STAR experiment.
Recently, the STAR collaboration reported a nonmonotonic beam energy dependence of the fourth-order fluctuations
of net-proton multiplicity distributions, which could hint a signal from the QCD critical end point
at $\sqrt{s_{\rm NN}}\approx7.7$ GeV.
In this talk, we will present results on fluctuations of net-particle distributions from the BES-I program.
Recent progress on the fifth- and sixth-order fluctuations will be reported,
and will be compared to theoretical calculations.
Future prospects for new data from BES-II and fixed-target programs will be also discussed.
In this talk we present an updated version of event generator THESEUS, based on the three-fluid dynamics (3FD), supplemented by UrQMD cascade for the late stage of the nuclear collision.
The generator gives opportunity to simulate light-nuclei production in relativistic heavy-ion collisions via thermal mechanism, on the same basis as hadrons. The generator is designed for BES-RHIC, SPS, NICA and FAIR collision energies.
Rapidity, transverse momentum spectra, first $v_1$ and second $v_1$ flow harmonics of deuterons, tritons, $^3$He are demonstrated for heavy-ion collisions at RHIC BES range. The results are compared with experimental data from NA49 and STAR.
The anti-deuteron spectra from THESEUS are in good agreement with STAR data. The contributions from the excited states of Helium to the yields of deuteron, triton and $^3$He are presented.
The reproduction of light nuclei spectra is reached without any extra fitting parameters, while in the original coalescence approach in 3FD it is necessary to adjust the coalescence coefficients for each light nucleus separately.
Within the transport model PHSD we analyze properties of the medium created at different stages of heavy-ions collision at NICA energies.
Nucleons of colliding nuclei are separated in participants and spectators, and the transition initial angular momentum to the fireball of participants is investigated.
Criteria for the selection of events with the highest internal angular momentum for various energies and colliding nuclei are proposed.
Fluidization of particle ensembles generated in the PHSD code following the Landau-Lifshitz definition is discussed. Properties of the created fluid, e.g, temperature, density, and velocity distributions are analyzed.
The vorticity of the fluid is investigated. It is demonstrated that in the collisions two vortex rings with opposite vorticities at forward and backward rapidities. Properties of the rings and their evolution are investigated.
The mission of the Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt is to explore the QCD phase diagram at high net baryon densities likely to exist in the core of neutron stars. The CBM detector system is designed to perform multi-differential measurements of hadrons and leptons in central gold-gold collisions at beam energies between 2 and 11 A GeV with unprecedented precision and statistics. In order to reduce the systematic errors of the lepton measurements, which generally suffer from a large combinatorial background, both electrons and muons will be measured with the same acceptance. Up to now, no di-muon measurements have been performed in heavy-ion collisions at beam energies below 158A GeV. Results of performance simulations for muon identification in the CBM experiment using machine learning procedures will be presented.
The thermal fit to preliminary HADES data of Au+Au collisions at $\sqrt{s_{_{NN}}}=2.4$ GeV shows two degenerate solutions at $T\approx50$ MeV and $T\approx70$ MeV. The analysis of the same particle yields in a transport simulation of the UrQMD model yields the same features, i.e. two distinct temperatures for the chemical freeze-out. While both solutions yield the same number of hadrons after resonance decays, the feeddown contribution is very different for both cases. This highlights that two systems with different chemical composition can yield the same multiplicities after resonance decays.
The nature of these two minima is further investigated by studying the time-dependent particle yields and extracted thermodynamic properties of the UrQMD model. It is confirmed, that the evolution of the high temperature solution resembles cooling and expansion of a hot and dense fireball. The low temperature solution displays an unphysical evolution: heating and compression of matter with a decrease of entropy. These results imply that the thermal model analysis of systems produced in low energy nuclear collisions is ambiguous but can be interpreted by taking also the time evolution and resonance contributions into account.
[1] A. Motornenko, J. Steinheimer, V. Vovchenko, R. Stock and H. Stoecker,
``Ambiguities in the hadro-chemical freeze-out of Au+Au collisions at SIS18 energies and how to resolve them,'' [arXiv:2104.06036 [hep-ph]]
Recently, in 2020 the LHCb Collaboration searches a new doubly heavy $\Xi_{bc}^0$ baryon decaying into $D^0 pK^-$ having mass in the range from 6.7 - 7.2 $GeV/c^2$. To study the properties of $\Xi_{bc}^0$ baryon (dcb) containing two different heavy quarks gives an ideal platform to understand the hadron spectroscopy and Quantum Chromodynamics (QCD). Under the Regge phenomenology, we have derived relations between intercept, slope ratios, and baryon masses. With the aid of these relations, we estimated the ground state mass of the newly observed $\Xi_{bc}^0$ baryon. Our calculated ground state mass is in consistent with experimentally observed mass and also reasonably close to other theoretical predictions. Our prediction could provide useful information in future experimental searches.
Based on work 2105.11102 (https://doi.org/10.1016/j.physletb.2021.136524).
We argue that the fixed target experiment PS191 operating on a proton beam of 19.2 GeV at CERN in the eighties was sensitive to hypothetical light scalars produced by mesons and decaying to charged particles. The experiment was dedicated to searches for sterile neutrinos produced in weak meson decays and decaying into final states with pairs of charged particles: electrons and muons. Two charged tracks from the same point have been adopted as the signal signature. Exploiting the same signature we use the negative results of searches at PS191 and place new limits on the light scalars coupled to the Standard Model (SM) particles via mixing with the Higgs boson. In particular, previously allowed region of masses 100--150 MeV and mixing above 4×10−4 is disfavored. Our analysis can be extended straightforwardly to models with other patterns of scalar couplings to SM particles.
The ENUBET experiment, included in the CERN Neutrino Platform effort as NP06/ENUBET, is developing a new neutrino beam based on conventional techniques in which the flux and the flavor composition are known with unprecedented precision ($\mathcal{O}$(1%)). Such a goal is accomplished monitoring the associated charged leptons produced in the decay region of the ENUBET facility. Positrons and muons from kaon decays are measured by a segmented calorimeter instrumenting the walls of the decay tunnel, while muon stations after the hadron dump can be used to monitor the neutrino component from pion decays. Furthermore, the narrow momentum width (<10%) of the beam provides a precise measurement ($\mathcal{O}$(10%)) of the neutrino energy on an event by event basis, thanks to its correlation with the radial position of the interaction at the neutrino detector. ENUBET is therefore an ideal facility for a high precision neutrino cross-section measurement at the GeV Scale, that could enhance the discovery potential of the next-generation of long baseline experiments. It is also a powerful tool for testing the sterile neutrino hypothesis and to investigate possible non-standard interactions.
In this contribution the design of the beamline and of the monitoring instrumentation will be shown. A new improved design of the proton target and of the meson transfer line ensures a larger neutrino flux while preserving a purity in the lepton monitoring similar to the one previously achieved. A demonstrator of the instrumented decay tunnel is currently being built and will be exposed to particle beams at CERN in 2022 to prove the effectiveness of the approach. Progress on the full simulation of the ENUBET facility and of the lepton reconstruction, towards the full assessment of neutrino flux systematics, will be also reported, together with the physics potential of the ENUBET beam.
The measurement of $\varphi$ meson production is a unique tool to explore the characteristics of the quark-gluon plasma (QGP). The $\varphi$ meson has a small interaction cross section and longer lifetime than the QGP, therefore its yields and elliptic flow are good probes of QGP properties. The $\varphi$ meson production might be sensitive to the strangeness enhancement in the QGP and can provide information about the flavor dependence of energy loss and elliptic flow. Measurements in different nucleus-nucleus collisions allow us to perform a systematic investigation of the nuclear matter effects, system size and geometry influence on $\varphi$ meson production.
The PHENIX experiment has measured transverse momentum spectra, nuclear modification factors $R_{AB}$, and elliptic anisotropy parameter $𝑣_2$ for $\varphi$ mesons in $𝑝$+Al, $𝑝$/$𝑑$/$^3$He/Cu+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and in U+U collisions at $\sqrt{s_{NN}}$ = 193 GeV at midrapidity (|$\eta$|<0.35). The obtained results exhibit scaling of $𝑣_2$ for $\varphi$ mesons with eccentricity of participant nucleons (collision geometry), whereas the $\varphi$ $R_{AB}$ values depend on the number of binary nucleon-nucleon collisions (system size). The comparison of experimental data on the $\varphi$ meson to various model calculations (AMPT, iEBE-VISHNU and Pythia 8) suggests importance of viscous hydrodynamics and the coalescence mechanism in describing the properties and hadronization of the QGP.
We study one of the important indirect signature of quark gluon plasma as electromagnetic signals. This work is carried out using a phenomenology of heavy-ion collisions in the limit of high temperature and chemical potential. The gamma gamma production rate is shown for lowest order process incorporating quark mass in the presence of chemical potential. The results are plotted in the relevant range of mass that is up to 4 GeV. Using a simple quasiparticle model, we found that gamma gamma emission spectra improved much in the presence of chemical potential. The results are useful and significant with the chemical potential.
Heavy-ion collisions quickly form a hot and dense phase of Quantum Chromodynamics (QCD) matter, so called the strongly interacting quark-gluon plasma (QGP). The QGP persists for only a much shorter time ($10^{-23}$s), then cools and translates into a lower temperature hadronic phase. Analyzing these final particles in a variety of different ways offers a unique insight into the properties of QGP and the complex dynamics of multi-scale processes in QCD. In this talk, several observables including the characteristic features of collective flow, chirality, and vorticity to understand this smallest and hottest droplet of liquid from recent STAR experimental preliminary results will be addressed.
We report the first measurement of the rapidity-odd directed flow ($v_1$) of multi-strange baryons ($\Xi$ and $\Omega$) in Au+Au collisions as recorded by the STAR detector at the Relativistic Heavy Ion Collider.
We focus on particle species where all constituent quarks are produced, as opposed to possibly transported, and demonstrate using a novel analysis method that the coalescence sum rule holds for hadrons with identical quark content. We examine the coalescence sum rule as a function of rapidity for non-identical quark content having the same mass but different strangeness ($\Delta S$) and electric charge ($\Delta q$). %For non-identical quark combination, a non-zero difference of directed flow, a measure of coalescence sum rule violation, has been observed, we call it directed flow splitting ($\Delta v_1$).
The difference in the directed flow of different quark and anti-quark combinations, e.g., $v_1(\Omega^{-}(sss)) - v_1(\bar{\Omega}^{+}(\bar{s}\bar{s}\bar{s}))$, is a measure of coalescence sum rule violation, and we call it directed flow splitting ($\Delta v_1$) between quarks and anti-quarks. This measurement uses the latest high statistics data sample from $\sqrt{s_{NN}}=$ 27 GeV Au+Au collisions where we take advantage of the improved event plane resolution of recently installed Event-Plane Detector (EPD). We measure $v_1$ as a function of rapidity; and then $\Delta S$ and $\Delta q$ dependence of the $\Delta v_1$-slope ($d\Delta v_1/dy$) between produced quarks and anti-quarks in Au+Au collisions at $\sqrt {s_{NN}} =$ 27 GeV and 200 GeV. The $d\Delta v_1/dy$ increases when $\Delta S$ and $\Delta q$ increase. This $d\Delta v_1/dy$ signal becomes weaker going from collision energy $\sqrt{s_{NN}}=$ 27 GeV to 200 GeV. We compare our measurements with the Parton-Hadron String Dynamics (PHSD) model + EM-field calculations.
We study the space-average electromagnetic (EM) fields weighted by the energy density in the central regions of heavy ion collisions. These average quantities can serve as a barometer for the magnetic-field induced effects such as the magnetic effect, the chiral separation effect and the chiral magnetic wave. Comparing with the magnetic fields at the geometric center of the collision, the space-average fields weighted by the energy density are smaller in the early stage but damp slower in the later stage. The space average of squared fields as well as the EM anomaly E.B weighted by the energy density are also calculated. We give parameterized analytical formula for these average quantities as functions of time by fitting numerical results for collisions in the collision energy range 7.7- 200 GeV with different impact parameters.
https://cern.zoom.us/j/68644475252?pwd=Q0dIcXI4WVc4T0Fsd1owQmROSml1QT09
We use Quantum Field Theory methods to we compute the bulk polarisation tensor of the materials, whose lattice tight-binding description permits a low-energy approximation in terms of Dirac fermion quasi-particles.
We study bulk dielectric functions of such Dirac materials at imaginary frequencies in the presence of a mass gap, chemical potential, and temperature. By using these data (and neglecting eventual boundary effects), we study the Casimir interaction of Dirac materials. We describe in detail the characteristic features of dielectric functions and their influence on the Casimir pressure.
We present the results of a first-principles lattice study of the Chiral Separation Effect in finite-density gauge theory with dynamical fermions. We find that the CSE is well described by the free quark result in the high-temperature quark-gluon plasma phase. As one enters the confinement regime with broken chiral symmetry at chemical potential smaller than half of the pion mass, the CSE response is gradually suppressed towards low temperatures in comparison to the free quark result. This suppression can be approximately described by assuming that the CSE current is proportional to the charge density, rather than the chemical potential, as suggested in ArXiv:1712.01256. We also present numerical evidence for the enhancement of the CSE response in the presence of heavy quarks, which, according to ArXiv:2012.15173, might be a manifestation of Kondo effect in non-Abelian gauge theory.
Hydrodynamic instabilities driven by a direct current are analyzed in two-dimensional (2D) and three-dimensional (3D) relativistic-like systems with the Dyakonov-Shur boundary conditions supplemented by a boundary condition for temperature. Besides the conventional Dyakonov-Shur instability for plasmons, we find a novel entropy wave instability in both 2D and 3D systems. The entropy wave instability is a manifestation of the relativistic-like nature of electron quasiparticles and a nontrivial role of the energy current in such systems. It is noticeable that these two instabilities could occur for the opposite directions of fluid flow. While the Dyakonov-Shur instability is characterized by the plasma frequency in 3D and the system size in 2D, the frequency of the entropy wave instability is tunable via the system size and the flow velocity.
In fall 2021, the accelerator complex of the Booster and Nuclotron at the Nuclotron Based Ion Collider Facility (NICA) at JINR (Dubna) will be ready to accelerate heavy ions. At the same time, the Baryonic Matter at Nuclotron (BM@N) experimental setup is completing its configuration to investigate relativistic heavy-ion beam interactions with fixed targets.
One of the most important experimental tasks of the BM@N physics program is determination of the equation of state of the high density baryonic matter. This task can accomplished via measurements of the (multi)strange hyperon excitation function, i.e. hyperon yields at different energies.
In the talk, the results of the Monte Carlo simulation of the BM@N detector performance for studying strangeness production in heavy-ion interactions will be presented.
The Compressed Baryonic Matter (CBM) experiment is one of the major scientific pillars of the future Facility for Antiproton and Ion Research (FAIR), which presently is under construction adjacent to the GSI Helmholtz Centre in Darmstadt, Germany, and is expected to come under operation in 2025. The goal of the CBM at FAIR is to explore the QCD phase diagram in the region of high baryon densities using high-energy nucleus-nucleus collisions (up to 11 AGeV Au-Au). This gives CBM a unique access to study the intricate nuclear physics of the astrophysical objects and events in laboratory in a controlled and precise manner by utilizing the peak beam-target interaction rates of up to 10 MHz.
This contribution will give an overview of the CBM physics program and goals, i.e., the study of the equation-of-state of dense nuclear matter, the possible phase transition from hadronic to partonic phase and chiral symmetry restoration. The status of various detector sub-systems and physics performance results showing CBM’s capabilities to detect the respective experimental observables will also be discussed. Additionally, various FAIR Phase-0 activities will also be addressed, which have proven to be crucial in the CBM’s preparation and understanding towards a functioning Day-1 setup.
From several heavy-ion collision (HIC) experiments at relativistic energies (ALADiN, KaoS, FOPI, ASY-EOS) performed with the SIS accelerator at GSI Darmstadt in the last three decades, a density dependence of the nuclear equation of states can be drawn from 0.3 to 2 times the saturation density, for both the symmetric matter (KaoS, FOPI experiments) and the symmetry energy part of the nuclear matter equation of states (AsyEOS and ALADiN). The density dependence of the pressure in neutrons stars deduced from such experiments confirms the results from most recent and precise gravitational wave and astrophysical multi-messenger measurements with a similar accuracy. Furthermore, this competitive input of HIC’s to the knowledge of neutron star properties can be much improved by increasing both the precision of measurements and probed densities. It is in this perspective that the ASY-EOS Collaboration has launched a new program of experiments at higher incident energies.
The QCD phase diagram in the region of large baryon-chemical potentials is increasingly attracting interest within the nuclear and astrophysics community. Heavy-ion collision experiments in the laboratory and astronomical observations complement each other, in order to explore the equation-of-state and the elementary degrees-of-freedom of high-density matter. Presently, the Baryonic Matter@Nuclotron (BM@N) experiment at JINR in Dubna is being upgraded in order to investigate Au+Au collisions at beam energies of up to 3.8A GeV, where matter densities like in compact stellar objects can be transiently created. The BM@N physics program including the relevant experimental observables and the expected performance of the detector system will be discussed.
Rayleigh scattering refers to the 2nd order QED process where a photon is scattered by a bound electron without a change in the photon energy [1]. For photon energies up to the MeV range it is the dominant contribution to the fundamental photon-matter interaction process of elastic scattering. This process is highly polarization-sensitive, making the analysis of polarization transfer in Rayleigh scattering suitable for a stringent test of the underlying theory [2].
A first experiment where an incident highly linearly polarized hard x-ray beam was used and the degree of linear polarization of both the incident and the scattered radiation was observed was performed in the work of Blumenhagen et al. in 2015 at the synchrotron facility PETRA III at Hamburg [3]. In this experiment the polarization-dependent features of the radiation being Rayleigh scattered within the polarization plane of the incident beam were analyzed. For the measurement of the polarization characteristics of the scattered radiation a prototype 2D sensitive strip detector, which was developed in the framework of the SPARC collaboration for precise and efficient x-ray polarimetry, was used serving as a dedicated Compton polarimeter [4]. Well in accordance with theory a dependence of the degree of linear polarization on the polar scattering angle and the degree of polarization of the initial beam was observed.
In a recent follow-up experiment we performed at the beamline P07 of the synchrotron facility PETRA III at DESY we extended on this previous measurement. For the first time, the polarization-dependent fea-tures of the Rayleigh scattered beam were measured outside the polarization plane of the incident, high-ly linearly polarized hard x-ray beam. For this experiment, the hard x-ray beam delivered by the synchro-tron which was set to a photon energy of 175 keV was scattered on a gold foil target of 1 µm thickness. The scattered radiation was detected by an improved prototype Compton polarimeter [5], also devel-oped in the framework of the SPARC collaboration, which was located under several scattering angles in-side and outside of the polarization plane of the initial beam.
Preliminary results show a strong dependence of the orientation of the polarization vector of the scat-tered beam with respect to the scattering plane on the polar and azimuthal scattering angles outside the polarization plane of the incident beam.
This research has been conducted in the framework of the SPARC collaboration. Financial support by ErUMFSP APPA (BMBF n° 05P19SJFAA) is acknowledged.
[1] P.P. Kane et al., Phys. Rep. 140, 75 (1986)
[2] Strnat et al. Phys. Rev. A 103, 012801 (2021)
[3] K.-H. Blu-menhagen et al., New J. Phys. 18, 103034 (2016)
[4] G. Weber et al., J. Phys.: Conf. Ser. 583, 012041 (2015)
[5] M. Vockert et al., NIM B 408, 313 (2017)
ATLAS searches conducted for a BSM light boson using as portal events where a Higgs
boson with mass 125 GeV decays to four leptons will be reported. This decay is presumed
to occur via an intermediate state which contains one or two on-shell, promptly decaying
bosons: H → ZX/XX → 4l, where X is a new dark vector boson Ζd (or a pseudo-scalar α),
with mass between 1 and 60 GeV. These exotic Higgs decays searches using pp collisions
data collected with the ATLAS detector at the LHC will be described. The results are found
to be consistent with SM background predictions and limits are set with interpretations in
specific benchmark theory models.
The off-shell production of SM Higgs boson, at the high-mass off-peak region beyond
2mZ, well above the measured resonance mass of mH=125 GeV, has a substantial cross
section at the LHC, due to the increased phase space as the Z bosons become on-shell
with the increasing energy scale. This presents a novel way of characterizing the
properties of the Higgs boson in terms of the off-shell event yields, normalized to the
SM prediction (referred to as signal strength µ), and the associated off-shell Higgs
boson couplings. Assuming the ratio of the Higgs boson couplings to the SM predictions
is independent of the momentum transfer of the Higgs boson production mechanism, a
combination with the on-shell signal-strength measurement was used to set indirect
limits on the total Higgs boson width with the ATLAS data collected in proton-proton
collisions at the centre-of-mass energy of √s = 13 TeV (36 fb-1).
Experimental studies demonstrate existence of unexplained correlations in biological systems at the distances much larger than quantum mechanics predicts. In particular, kidney and liver cells, blood erythrocytes identify their partner cells and reject wrong ones at the distances which are much larger than the range of chemical forces; no reasonable explanation of such phenomena exist (Vitiello, 2001, Bischof, 2003). It was assumed previously that such effects can be induced by EPR-Bohm nonlocal correlations (NC) (Primas, 1982; Josephson, 1991), however, such particular NC mechanism was shown to be inconsistent. Meanwhile, it was argued that quantum NC can be more general concept than standard EPR-Bohm one and, in principle, some other NC mechanisms can exist (Stapp, 1997; Cramer, 1986). Basing on these ideas, we propose model, in which NC induces nonlocal corrections to Schrodinger Hamiltonian of large system. Due to them, for two distant subsystems the transition between states of one subsystem changes the rate of analogous transitions in other distant subsystem resulting in the evolution similarity between them; such effect, in principle, can result in observed bio-system correlations.
Bischof M (2003) in Integrative Biophysics, Popp F-A, Beloussov, L V (eds.). . Kluwer Academic Publishers, Dordrect
Cramer J. (1986) Rev. Mod. Phys. 58, 647
Josephson B.D., Pallikari-Viras F. (1991) Found. Phys. 21, 19
Primas H (1982) Chemistry 36, 293
Stapp H. P. (1997) Am.J. Phys. 65, 300
Vitiello G. (2001) My Double Unveiled. John Benjamins, Amsterdam
Quarkonia are an important probe into studying the properties of quark-gluon plasma. Proton-proton collisions serve as an essential baseline for studying the effects of quarkonia in proton-nucleon and nucleon-nucleon collisions. This poster presents the main characteristics of Upsilon mesons from Monte Carlo generation of proton-proton collisions at $\sqrt{s}$ = 500 GeV. Monte Carlo event generators PYTHIA and Herwig were used to generate the data. Main aim of the simulations is to explore the dependence of normalised Upsilon meson yield on normalised event multiplicity. Normalised multiplicity dependence is a meaningful tool for understanding the particle production mechanisms and the interplay between soft and hard QCD processes.
This paper contains the results on an attempt to simultaneously accelerate a three-charge state Uranium beam with 59 - 61+ charge states after the stripper section in the SC section of an accelerator-driver LINAC-100. Beam fractions oscillations along the SC part of LINAC-100 are investigated, quasi-synchronous phase pattern along the linac SC part was optimized to mitigate beam fractions "tails" occurring due to the large phase slipping rate inside the cavities considering the most possible accelerating rate preservation.
In general, the design and construction of CW high-intensity linacs are one of the crucial goals of worldwide accelerator technology development. Such linacs are useful for large-scale research complexes as SNS or ADS. Also, they are usually used as driver-accelerators for radioactive ion beams facilities. Developing an initial part of these linacs is an especially difficult issue. Currently, CW-RFQ ion linacs are used for this. This overview is about accelerating structures applied in these CW-RFQs.
The study of x-ray emission associated with Radiative Recombination at “cold” temperature conditions, as it prevails at electron cooler devices in ion storage rings, allows for a stringent test of atomic structure and the subsequent x-ray emission characteristics. In particular, for heavy, highly charged ions at high Z it enables to investigate in detail the prevailing cascade decay dynamics and provides detailed insight into the final state population of the recombination process itself.
We report on an experiment where bare lead ions (Pb$^{82+}$) were decelerated down to 10 MeV/u in the ESR storage ring at GSI-Darmstadt and injected into CRYRING@ESR [1] and, subsequently, the x-ray emission of H-Like Pb associated with radiative recombination were studied at the electron cooler. For this purpose, at the electron cooler dedicated vacuum chambers were used, equipped with beryllium view ports allowing for x-ray detection under 0° and 180° with respect to the ion beam axis. The x-ray detection was accomplished by using two standard high-purity germanium x-ray detectors. In order to suppress the dominant background, stemming from x-ray emission by the electron beam (bremsstrahlung) and the natural background, an ion detector (channel electron multiplier) was operated downstream to the cooler, enabling to record x-rays in coincidence with down-charged Pb$^{81+} $ions from electron-cooler section.
Even though in this very first beam time with bare, decelerated high-Z ions in CRYRING@ESR only a low intensity of 2×10$^{5}$ ions per injection was possible, a few days of continuous operation were sufficient to accumulate meaningful spectral information when combining the signals in both x-ray detectors with the particle detector. The x-ray spectrum associated with radiative recombination is governed by intense Ly-$\alpha$ radiation as well as by Balmer and even Paschen transition providing a unique opportunity for finale-state selective recombination studies.
This research has been conducted in the framework of the SPARC collaboration, experiment E138 of FAIR Phase-0 supported by GSI. It is further supported by the European Research Council (ERC) under the European Union's Horizon 2020 research as well as by the innovation program (Grant No 682841 "ASTRUm") and the grant agreement n° 6544002, ENSAR2. B. Zhu acknowledges CSC Doctoral Fellowship 2018.9-2022.2; we acknowledge substantial support by ErUM-FSP APPA (BMBF n° 05P19SJFAA) too.
Reference:
[1] M. Lestinsky et al., Eur. Phys. J.-Spec. Top. 225, 797 (2016)
We have designed, built and operated the HILITE (High-Intensity Laser Ion-Trap Experiment) Penning trap which is designed to extend the research of the interaction of high-intensity or high photon-engergy laser pulses to highly-charged ions. The binding energy of electrons in highly-charged ions such as hydrogen-like carbon is comparable to the photon energy of XUV to X-ray free-electron lasers and are now accessible by multi-photon ionisation. The electric field between an electron in hydrogen-like neon is comparable to the electric field of a high-power laser with an intensity of about $10^{20} \frac{W}{cm^2}$ and can be ionised via field ionisation. In the mentioned systems, ionisation cross sections can be predicted precisely by theoretical models with comparably little computational effort and can be hence compared with the experimental values. It is also possible to measure the laser intensity in case the ionisation cross sections are known.
Using a Penning trap we can compose a single-species ion-cloud with well-known ion charge state, ion number and ion-cloud shape. The trap is built in the so-called open-endcap design to allow both laser and ion access from outside. The ions are produced externally by an Electron-Beam Ion Trap (EBIT), selected by a Wien filter, and captured dynamically in the trap centre [1].
For example, $\text{C}^{2+}$ and $\text{C}^{5+}$ ions have been captured, detected inside the ion trap and stored for roughly a quarter of an hour. In addition, we have characterised the ion trap content destructively after ion ejection using time-of-flight spectroscopy.
For ion-cloud formation, a cycle time of less than one minute is aspired, for which the current storage time is sufficient.
Last year we have moved the HILITE Penning trap to a photon user facility for the first time, in the present case FLASH at DESY in Hamburg. We have connected both systems and brought the trap back in operation successfully. We have had to deal with unexpected bad vacuum conditions which has allowed us only the storage of $\text{C}^{2+}$ ions for a short time. We have used the 10 Hz master clock of the FLASH FEL to synchronise the ion capture, ejection and detection procedure with the laser pulses. During laser-ion interaction, the ions have been located about 20 mm around the trap centre in axial direction where the laser waist diameter has been nearly constant. This allowed for a good overlap of the stored ions with a laser focus of a well-known shape. The interaction of the laser with the stored ions has lead to loss of the initially stored $\text{C}^{2+}$ ions which can be assigned to laser ionisation.
We will present the setup, the commissioning results and results from our first beamtime. We will also present envisaged upgrades of the setup.
[1] N. Stallkamp et al. X-Ray Spectrom 49(2020) 188-191
The CDCS is an interdisciplinary cooperation among the German Electron Synchrotron DESY, Universität Hamburg, and the Hamburg University of Technology. In the newly emerging Science City Bahrenfeld (SCB), it combines scientific research with state-of-the-art information technology.
The CDCS initially consists of four application-focused, cross-disciplinary laboratories (CDLs), which are supported by a Computational Core Unit (CCU). The CDLs focus on the following areas:
In this poster, we present various ongoing projects and prospects for the coming years.

The recent experimental result on the muon g-2 from Fermilab has confirmed the old Brookhaven result and increased the tension with the Standard Model. We investigate the electroweak sector of supersymmetry to explain the muon g-2 anomaly. We perform a scan of the SUGRA parameter space with the help of a neural network to identify the regions consistent with the g-2 anomaly. It is shown that a gluino-driven radiative breaking of the electroweak symmetry is a natural outcome with the sleptons and weakinos being low-lying while the colored sector is heavy. To perform a SUSY search at the LHC using a set of benchmarks, we employ a deep neural network to train the signal and background. We show that benchmarks corresponding to slepton and sneutrino production can be discovered at HL-LHC and HE-LHC.
The talk is based on arXiv:2104.03839 [hep-ph].
Surrounding Matter Theory [1], an alternative theory to dark matter, is reminded. Some mathematical developments of the model are presented. First, the Poincare-Einstein synchronization of clocks [2] is revisited in the context of SMT. For this a particular Euclidean view of relativity [3] gives some insight. Then is studied a different interpretation of GR principles using the mathematical duality of null versus non null vectors in the GR degenerated metric. Finally a development of the Surrounding equation in the context of Particle Physics is tried.
The current status of holographic QCD (HQCD) applications to the studies of the formation and properties of quark-gluon plasma produced in heavy ions collisions will be presented.
I will take special attention to effects predicted by HQCD at high baryon densities attainable at the NICA experimental complex as well as to effects of rotations and huge magnetic fields in a produced quark-gluon plasma.
T2K is an accelerator-based neutrino experiment providing world-leading measurements of the parameters governing neutrino oscillation. T2K data enabled the first 3sigma exclusion for some intervals of the CP-violating phase \delta_{CP} and precision measurements of the atmospheric parameters \Delta_m^{2}{32}, sin^2(\theta{23}). T2K uses a beam of muon neutrinos and antineutrinos produced at the Japan Particle Accelerator Research Centre (JPARC) and a series of detectors located at JPARC and in Kamioka, 295km away, to measure oscillation from neutrino event rates and spectra. The T2K beam will be upgraded with increased power in 2022 and, combined with an upgrade of the ND280 near detector, will usher in a new important physics period for T2K. In addition, the Super-Kamiokande detector has been loaded with 0.02% of Gadolinium in 2020, enabling enhanced neutron tagging.
In preparation for the new physics run, the T2K collaboration is working on an updated oscillation analysis to improve the control of systematic uncertainties. A new beam tuning has been developed, based on an improved NA61/SHINE measurement on a copy of the T2K target and including a refined modeling of the beam line materials. New selections have been developed at ND280, with proton and photon tagging, and at Super-Kamiokande, where pion tagging has been extended to muon neutrino samples. After reviewing the latest measurements of oscillation parameters, the status of such new analysis developments and the plan to deploy the beam and ND280 upgrade will be presented.
The searches for light Higgs bosons after the discovery of the 125 GeV Higgs boson would be presented with the proton collision data collected by the CMS experiment at the LHC at a centre-of-mass energy of 13 TeV. The searches for light pseudoscalar Higgs bosons pair produced from the decay of the 125 GeV Higgs boson and resulting in various final states (4$\mu$, 4$\tau$, 2$\mu$2$\tau$ and 2b2$\tau$) according to the mass range of the light boson will be summarised. The search for a light pseudoscalar Higgs boson decaying to tau pairs and produced in association with a bottom quark will be presented for the light boson mass range of 25 to 70 GeV. A search for CP-odd Higgs boson decays to two muons in the mass range between 15 and 75 GeV will also be presented. Moreover, the search for low mass scalar bosons below 125 GeV in decays to photon pairs will be highlighted.
SoLid (Search for short oscillation using $^6$Li detector) is measuring the flux of electron anti-neutrinos close to the 60 MW BR2 nuclear reactor at SCK$\bullet$CEN in Mol, Belgium. The detector is installed at a distance of just over 6 m from the compact reactor core and is constructed from an array of 5x5x5 cm$^3$ PVT based scintillator cubes, which are optically coupled to $^6$Li:ZnS(Ag) scintillator foils. Neutrinos are detected through the inverse Beta Decay (IBD) reaction. The resulting positron is detected through the scintillation light produced in the PVT, while the neutron thermalizes and is captured by the $^6$Li. Both scintillators have quite different signatures, which allow the separation of the electromagnetic and nuclear signals.
This presentation will give a motivation for the search for sterile neutrinos
followed by an introduction to the SoLid detector and the first physics results
after two years of data-taking. It will conclude with a description of to the detector upgrade in the summer 2020 and the perspective for the final measurements.
The evidence for the existence of dark matter, so far is based on its gravitational effects. Nevertheless, many theoretical models assume other non-gravitational very-weak interactions between dark matter and ordinary matter, and to test this hypothesis, different experiments are trying to directly detect dark matter signals at particle accelerators.
This elusiveness of dark matter has triggered innovative and open-minded approaches spanning a wide range of energies with high-sensitivity detectors. In this scenario is inserted the Positron Annihilation into Dark Matter Experiment (PADME) ongoing at the Frascati National Laboratory of INFN. PADME is searching a Dark Photon signal [1] by studying the missing mass spectrum of single photon final states resulting from positron annihilation events on the electrons of a fixed target. After commissioning and beam-line optimization, PADME collected in 2020 about 5×1012 positrons on target.
Actually, the PADME approach allows to look for any new particle produced in e+e− collisions through a virtual off-shell photon such as long lived Axion-Like-Particles (ALPs), proto-phobic X bosons, Dark Higgs ... In the talk, the scientific program of the experiment, and its current status will be illustrated.
References
[1] B. Holdom, Phys. Lett B 166, 196 (1986).
The forward BFKL equation is discretized in order to understand momenta difussion into the infrared and ultraviolet by means of a semi-infinite matrix. This matrix is square truncated so an exponentiation is possible, leading to asymptotic eigenstates related to the gluon Green's function at large matrix size. There is also a relation between this truncation and the XXX Heisenberg spin=-1/2 chain. A modification to the matrix results on an evolution more compatible with the Froissart bound.
The present work is mainly focussed on the estimation of the level scheme of $ K=0$ and $K=5$ bands in ${^{240}Am}$ using TQPRM model. While exploring the actinide region we have noticed that the experimental level scheme is not systematic to study the properties of ${^{240}Am}$ nucleus. We have also made the comparison between the theoretical energies and experimental energies which lead us to predict the correct spins of each level. The available experimental data is having mixed states so, it is a significant effort to predict the unique level scheme for both the bands for further investigations in this nucleus.
Kyrill Bugaev$^{a, b}$, Oleksandr Vitiuk$^{c}$, Valery Pugatch$^{c}$, Vasyl Dobishuk$^{c}$, Sergiy Chernyshenko$^{c}$, Boris Grinyuk$^{b}$, Pavlo Panasiuk$^{a}$, Nazar Yakovenko$^{a}$, Elizaveta Zherebtsova$^{d}$, Larissa Bravina$^{e}$, Arkadiy Taranenko$^{d}$, Evgeny Zabrodin$^{e, f}$
and Marcus Bleicher$^{g}$
$^{a}$Department of Physics, Taras Shevchenko National University of Kyiv, 03022 Kyiv, Ukraine
$^{b}$Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine, Metrologichna str. 14-B, 03680 Kyiv, Ukraine
$^{c}$Institute for Nuclear Research, National Academy of Sciences of Ukraine, Prospekt Nauki av. 47, 03680 Kyiv, Ukraine
$^{d}$National Research Nuclear University “MEPhI” (Moscow Engineering Physics Institute), Kashirskoe Shosse 31, 115409 Moscow, Russia
$^{e}$University of Oslo, POB 1048 Blindern, N-0316 Oslo, Norway
$^{f}$Skobeltsyn Institute of Nuclear Physics, Moscow State University, 119899 Moscow, Russia
$^{g}$Institute for Theoretical Physics, Goethe University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main, Germany
We suggest to explore an entirely new method to experimentally and theoretically study the phase diagram of strongly interacting matter based on the triple nuclear collisions (TNC). The key element of such experiments is to use the superthin solid target operated in the core of two colliding beams [1]. Our approach is based on the successful data-taking in the LHCb experiment in which the colliding and fixed gaseous target modes are running simultaneously [2]. The estimates show that under the high luminosity LHC conditions the TNC rate might reach an observable level of 1 event over 1000 s.
We simulated the TNC using the UrQMD 3.4 model [3, 4] at the beam center-of-mass collision energies √s = 200 GeV and √s = 2.76 TeV. It is found that in the most central and simultaneous TNC the initial baryonic charge density is about 3 times higher than the one achieved in the usual binary nuclear collisions at the same energies [5]. As a consequence, a production of protons and Λ-hyperons is increased by 2 and 1.5, respectively, while a sizable suppression of their antiparticles is observed.
At the beam center-of-mass collision energies of 10-40 GeV, the production of protons as well as of Λ-hyperons is enhanced approximately by a factor of 2.2 compared to the binary collisions, while the positive kaons are enhanced by 1.5. Hence we conclude that in the TNC method it is possible to create substantially denser strange matter than in the binary collisions. It is argued that this method at lower energies can be of principal importance for searching the (tri)critical endpoint of the QCD phase diagram [5].
References:
[1] V. Pugatch, International Conference "CERN-Ukraine co-operation: current state and prospects“ Kharkiv. 15-May-2018; LHCb-TALK-2018-557.
[2] LHCb Collaboration. SMOG2.Tecnical Design Report. CERN-LHCC-2019-005l.
[3] S.A. Bass et al., Prog. Part. Nucl. Phys. 41 (1998), 225-370.
[4] M. Bleicher et al., J. Phys. G 25 (1999), 1859-1896.
[5] K. Bugaev et al., talk at the Online «Strangeness in Quark Matter» Conference 2021, Brookhaven, May 17-22, 2021; https://indico.cern.ch/event/985652/sessions/392917/#20210521
Jets are produced in heavy-ion and nucleon-nucleon collisions from hard-scattered patrons of the incoming beams. We can infer the property of hot-dense QCD matter, known as Quark-Gluon Plasma (QGP), by studying the modified jet properties in heavy-ion collisions with respect to their vacuum reference. The STAR experiment has recently reported several novel jet measurements in heavy-ion collisions that provide information about the medium-induced parton energy loss at RHIC. In central Au+Au collisions at $\sqrt s_{\rm NN}$ = 200 GeV, the inclusive charged-particle jet yields show a strong suppression for different jet resolution parameters (R), whereas the semi-inclusive direct-photon and hadron triggered recoil jet measurements hint at a R dependent jet suppression. We compare these measurements with those at the LHC and investigate the parton energy loss in QGP by comparing jet transverse momentum shift at different collision energies. Besides, we study the QCD parton shower and jet evolution in vacuum by measuring different jet substructure observables in p+p collisions. For example, the SoftDrop groomed jet mass, shared momentum fraction, and groomed jet radius are measured in p+p collisions at $\sqrt s$ = 200 GeV, and compared with different QCD-based models. Finally, we will discuss the forthcoming STAR experiment data-taking plan during the final stage of RHIC running and the improved precision achievable for jet measurements.
Quarkonium states are good probes allowing to study the properties of quark-gluon plasma created in heavy ion-collisions. However, the production mechanism in p+p collisions is still an open question. It is often assumed that it factorizes into the hard scattering and non-perturbative hadronization. The basic quarkonium production models like Color Singlet, Color Octet and Color Evaporation Model can reasonably well describe different aspects of quarkonium production. A new observables, which include associated production or quarkonium production in jets may provide a more detailed insight into this topic. Furthermore, studies of quarkonium production vs. charged particle multiplicity allow to study an interplay between hard and soft QCD processes. Overall, measurements of quarkonium production in p+p collisions provide tests of QCD.
In this presentation, an overview of experimental results of quarkonium production in p+p collisions at RHIC and LHC will be presented along with current production models.
Jets are collimated sprays of hadrons created by the fragmentation of high energy partons, and serve as an experimental tool for studying quantum chromodynamics. In particular, we can explore the properties of parton showers and jet evolution by measuring jet sub-structure. One of the techniques that allows experimental access to the parton shower is the jet grooming technique called SoftDrop. This analysis extends recent measurements of the jet sub-structure observables based on the SoftDrop algorithm in p+p collisions at $\sqrt{s}$ = 200 GeV in the STAR experiment, including groomed radius ($R_{g}$) and shared momentum fraction ($z_{g}$). We present fully unfolded multi-differential measurements of jet sub-structure observables at the first split and their corresponding correlations via $z_{g}$ vs. $R_{g}$ for jets of different transverse momenta and radii. We show that $z_{g}$ has a strong dependence on $R_{g}$ and a weak dependence on jet transverse momentum. To further explore the jet sub-structure, we present the first measurement of the jet shower at the first, second and third splits via the iterative SoftDrop procedure. For each of these splits, we measure the fully corrected $z_{g}$ and $R_{g}$. We compare our measurements to the state-of-the-art Monte Carlo models. We discuss the impact of variations in parton shower (perturbative) and hadronization/underlying-event (non-perturbative) modeling on the measured correlations between sub-structure observables. We will also preview upcoming measurements that explore the splitting scale ($k_{T}$) and groomed mass fraction ($\mu$) in our differential framework.
Due to their simplicity and comparatively low cost Resistive Plate Chambers are gaseous detectors widely used in high-energy and cosmic rays physics when large detection areas are needed. However, the best gaseous mixtures are currently based on tetrafluoroethane, which has the undesirable characteristic of a large Global Warming Potential (GWP) of about 1400 and, because of this, it is currently being phased out from industrial use. As a possible replacement, tetrafluoropropene (which has a GWP close to 1) has been taken into account.
Since tetrafluoropropene is more electronegative than tetrafluoroethane, it has to be diluted with gases with a lower attachment coefficient in order to maintain the operating voltage close to 10 kV. One of the main candidates for this role is carbon dioxide. In order to ascertain the feasibility and the performance of tetrafluoropropene-CO2 based mixtures, an R&D program is being carried out within the ALICE collaboration, which employs an array of 72 Bakelite RPCs (Muon Identifier, MID) in order to identify muons. Different proportions of tetrafluoropropene and CO2, with the addition of small quantities of isobutane and sulphur hexafluoride, have been tested with 50x50 cm2 RPC prototypes with 2 mm wide gas gap and 2 mm thick Bakelite electrodes.
In this contribution, results from tests with cosmic rays will be presented, together with data concerning the current drawn by a RPC exposed to the gamma-ray flux of the Gamma Irradiation Facility (GIF) at CERN.
Experiments with antiprotons often require the tracking of the charged particles emerging from the annihilation process. The ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration at the CERN Antiproton Decelerator (AD) has used several panels of scintillating bars placed around an interaction region to reveal the passage of charged pions and determine the annihilation vertex position and time.
The panels are composed of ~1$~$m long extruded scintillating bars with a cross section of 1.5x2.0$~$cm$^2$ and a hole along the bar axis with WLS fibers glued to collect the light. Several fibers are grouped and readout by multi-anode PMTs for a total of ~500 readout channels.
After operating for several years, the fiber-PMT coupling has degraded and a major upgrade of the light readout system has been planned. The PMTs will be replaced by SiPMs with an active surface of 1$~$mm$^2$ (1 SiPM per fiber) and the front-end electronics will be changed accordingly. An improvement is expected in the efficiency and the uniformity of the detector response, moreover it will be possible to work in magnetic field regions.
In this contribution the commissioning of the upgrade will be described and expected performances discussed. Preliminary tests with cosmic rays have been completed, the light yield of a single bar has been measured and the fiber-SiPM system validated. The front-end electronics to cope with the new signal source have been designed and prototype boards tested. The mechanical structure has been adapted and the final assembly is ongoing.
The Monitored Drift Tube (MDT) provides precise tracking and momentum measurement in the ATLAS muon spectrometer. To accommodate higher event rates and provide better fake rejection in the High Luminosity LHC, a new integrated chamber with small-diameter MDT (sMDT) and thin Resistive Plate Chambers (tRPC) had been developed and will be installed into barrel inner layer of the muon detector for the phase-2 upgrade. The BIS78 project serves as a pilot project for the barrel inner layer upgrade (1 < |η| < 1.3). During the LHC LS1 shutdown (2019-2021) several sMDT+tRPC chambers have been installed and operated in the ATLAS detector. An overview of the commissioning status of BIS78 in the ATLAS experiment will be presented.
The ability to identify jets stemming from the hadronisation of b-quarks (b-jets) is crucial for the physics program of ATLAS.
The higher pileup conditions and the growing interest for measurements including c-jets and for searches in the high transverse momentum regime make the task more and more complex. The algorithms responsible for establishing the jet’s flavour are evolving quickly, exploiting powerful multivariate and deep machine learning techniques. Since the primary input to any such algorithm consists of charged-particle tracks within the jet, the identification of jets from heavy-flavor decays depends strongly on the tracking efficiency and resolution and the robustness of the track-jet association logic. Flavour-tagging techniques in ATLAS will be reviewed, presenting the state-of-the-art in terms of algorithms, with focus on the capability to reconstruct and select the relevant tracks produced in the ATLAS Inner Detector.
To meet new TDAQ buffering requirements and withstand the high expected radiation doses at the high-luminosity LHC, the ATLAS Liquid Argon Calorimeter readout electronics will be upgraded. Developments of low-power preamplifiers and shapers to meet low noise and excellent linearity requirements are ongoing in 130nm CMOS technology. In order to digitize the analogue signals on two gains after shaping, a radiation-hard, low-power 40 MHz 14-bit ADCs is developed in 65 nm CMOS. The signals will be sent at 40 MHz to the off-detector electronics, where FPGAs connected through high-speed links will perform energy and time reconstruction through the application of corrections and digital filtering. The data-processing, control and timing functions will be realized by dedicated boards connected through ATCA crates. Results of tests of prototypes of front-end components will be presented, along with design studies on the performance of the off-detector readout system.
The instantaneous luminosity of the Large Hadron Collider at CERN will be increased by about a factor of five with respect to the design value by undergoing an extensive upgrade program over the coming decade. The largest phase-1 upgrade project for the ATLAS Muon System is the replacement of the present first station in the forward regions with the New Small Wheels (NSWs) during the long-LHC shutdown in 2019-2021. Along with resistive strips Micromegas, the NSWs will be equipped with eight layers of small-strip thin gap chambers (sTGC).
The new system is designed to assure high tracking efficiency, reduction of fake trigger rates and precision measurement of muon tracks.
The two Small Wheels are called A and C and cover a positive and negative pseudorapidity acceptance in the range $|\eta|$ =1.3 to 2.7.
The commissioning in surface of the NSW-A at CERN has been successfully completed in the end of June 2021 and the wheel is currently under installation in ATLAS. The integration and commissioning of the NSW-C is well advanced, aiming at installation on October 2021.
The sTGC design, construction and integration status will be discussed, along with their performance studies obtained with cosmic rays during the detectors integration and validation phase.
The CMS high granularity calorimeter (HGCAL) is a challenging detector that brings together tracking and calorimetry with silicon and scintillators, as well as meet the harsh radiation and pileup environment in the forward rapidity region during the High Luminosity LHC phase and exploit challenging signatures such as VBF/VBS production towards new physics searches. The HGCAL will be realised as a sampling calorimeter, with layers of silicon pads and layers combining silicon and scintillator detectors interspersed with metal absorber plates. The HGCAL features unprecedented transverse and longitudinal segmentation in both its electromagnetic and hadronic compartments. This information allows to resolve the fine structure of the electromagnetic and hadronic showers, playing to the strengths of particle-flow reconstruction, and allowing to enhance pileup rejection and particle identification, while still achieving good energy resolution. The electromagnetic part and a large fraction of hadronic part of the calorimeter will be based on hexagonal silicon sensors of 0.5 - 1 cm$^{2}$ cell size. The remainder of the hadronic part will be based on highly-segmented scintillators read out by silicon photomultipliers. The intrinsic high-precision timing capabilities of the silicon sensors add a further measurement dimension critical in event reconstruction, especially for pileup rejection. This presentation will provide an overview of the HGCAL project covering the physics motivation, detector design, readout and trigger concepts, detector construction and tests.
Effect of Mn-Mg co-doped NiFe2O4 with composition Ni0.5-xMnxMg0.5Fe2O4 (x=0, 0.1, 0.2, 0.3, 0.4) was prepared by the hydrothermal method. All the samples were sintered at 900 oC for 3 hours and after appropriate heat treatments, their structural, electrical, and magnetic properties were investigated by using XRD, FESEM, TEM, FTIR, DC resistivity, and VSM respectively. XRD confirmed the formation of the spinel phase along with the increase in the crystallite size from 28 nm to 48 nm as the dopant concentration increased up to x=0.4. Both FESEM and TEM confirmed the formation of spherical grains. Similarly, FTIR spectroscopy also confirmed the strong metal bond in tetrahedral (A-site) and octahedral site (B-site) which again gave strong evidence of the formation of spinel phase. Magnetic properties like the retentivity (Mr), saturation magnetization (Ms), and coericivity (Hc) were reduced quite sharply and were found below 10 emu/g, 27.78 emu/g, and below 160 Oe. On the other hand, the Curie temperature (T c ) was found to reduce from 189 ̊C to 178 ̊C whereas the sharp increase in the DC resistivity along with the activation energy of 0.37 eV was observed. The observed magnetic and electrical properties of such material make them a suitable candidate for high-frequency applications where eddy current losses become appreciable.
Key Words: Ferrite, Sintering, Magnetic properties, Resistivity
We discuss the quantum fluctuations of energy in subsystems of hot relativistic gas for both scalar and spin half particles. For small subsystem sizes, we find a substantial increase of fluctuations compared to those known from standard thermodynamic considerations. However, if the size of the subsystem is sufficiently large, we reproduce the result for energy fluctuations in the canonical ensemble. Interestingly for spin half particles, the results for quantum fluctuation depend on the form of the energy-momentum tensor used in the calculations, which is a feature described as pseudo-gauge dependence. However, for sufficiently large subsystems the results obtained in different pseudo-gauges converge and agree with the canonical-ensemble formula known from statistical physics. As different forms of the energy-momentum tensor of gas are a priori equivalent, our finding suggests that the concept of quantum fluctuations of energy in very small thermodynamic systems is pseudo-gauge dependent. Our results can be used in the context of relativistic heavy-ion collisions to introduce limitations of the concepts such as classical energy density or fluid element. Also, the results of our calculations determine a scale of coarse-graining for which the choice of the pseudo-gauge becomes irrelevant. In a straightforward way, our formula for quantum fluctuation can be applied in other fields of physics, wherever one deals with hot and relativistic matter.
This report is devoted to the study of the influence of relativistic rotation on the confinement/deconfinement transition in SU(3) gluodynamics within lattice simulation. We perform the simulation in the reference frame which rotates with the system under investigation, where rotation is reduced to external gravitational field. To investigate the confinement/deconfinement transition the Polyakov loop and its susceptibility are calculated for various lattice parameters and the values of angular velocities which are characteristic for heavy-ion collision experiments. Different types of boundary conditions (open, periodic, Dirichlet) are imposed in directions, orthogonal to rotation axis. Our data for the critical temperature are well described by a simple quadratic function $T_c(Ω)/T_c(0)=1+C_2 Ω_2$ with $C_2>0$ for all boundary conditions and all lattice parameters used in the simulations. From this we conclude that the critical temperature of the confinement/deconfinement transition in gluodynamics increases with increasing angular velocity. This conclusion does not depend on the boundary conditions used in our study and we believe that this is universal property of gluodynamics.
In order to provide optimal reconstruction of charged tracks, the positions of the nearly twenty-thousands silicon sensors of the central tracking system of the CMS detector must be determined at a better precision than their in- trinsic resolution, under a procedure called alignment. At CMS, the alignment also includes the orientation and surface deformations of the sensors. Data- driven methods to carefully align the detector and validate the alignment are presented in the context of the legacy alignment for CMS Run-2 data, corre- sponding to the data accumulated from 2016 to 2018. Systematic distortions are discussed, such as weak modes and variations of the conditions during data taking over time, in particular effects related to the radiation damages. Finally, we discuss prospects for CMS Run-3.
The ALICE Inner Tracking System (ITS) has recently been replaced with a full silicon-pixel detector constructed entirely with CMOS monolithic active pixel sensors.
It consists of three inner layers (50 m thick sensors) and four outer layers (100 m thick sensors) covering 10 m2 and containing 12.5 billion pixels with a pixel size of 27 μm x 29 μm.
Its increased granularity, the very low material budget (0.35% X0/layer in the inner barrel) as well as a small radius of the innermost layer combined with a thin beam pipe, will result in a significant improvement of impact-parameter resolution and tracking efficiency at low pT with respect to the previous tracker.
The commissioning of the ITS within the ALICE apparatus has recently started. After a first phase of standalone tests and detector performance optimization the ITS has recently been included in the global commissioning activities.
Exploiting the flexibility of silicon when thinned down to thicknesses of O(50um), and the possibility of producing MAPS sensors of wafer size by a process known as stitching, the ALICE project is aiming at building detector elements that are large enough to cover full tracker half-layers with single bent sensors.
The ALICE ITS3 project is planning to build a new vertex tracker based on truly cylindrical wafer-scale sensors, with <0.05% X0 per layer and as close as 18 mm to the interaction point. R&D on all project aspects (incl. mechanics for bent wafer-scale devices, test beams of bent MAPS, design of stitched sensors) is rapidly progressing with the aim for installation during LHC LS3.
In this talk, the first results of the performance of the new ALICE ITS detector, studied during commissioning, will be presented, together with an overview of the ITS3 R&D status.
The increase of the particle flux (pile-up) at the HL-LHC with instantaneous luminosities up to
L ~ 7.5 × 10$^{34}$ cm$^{-2}$s$^{-1}$ will have a severe impact on the ATLAS detector reconstruction and trigger performance. The end-cap and forward region where the liquid Argon calorimeter has coarser granularity and the inner tracker has poorer momentum resolution will be particularly affected. A High Granularity Timing Detector (HGTD) will be installed in front of the LAr end-cap calorimeters for pile-up mitigation and luminosity measurement.
The HGTD is a novel detector introduced to augment the new all-silicon Inner Tracker in the pseudo-rapidi