Measurements of two-particle correlations in $pp$ collisions show the presence of long-range correlations along $\Delta\eta$ that are strikingly similar to those seen in heavy-ion collisions. In heavy-ion collisions, the long-range correlations are known to arise from the collective dynamics of the produced quark-gluon plasma (QGP). The similarity between the $pp$ and heavy-ion measurements...
Efforts to understand QGP signatures using perturbative QCD models have been an active field since the first observation of the near-side long-range two-particle correlations in p-p collisions at the LHC in 2010. On the other hand, tools like Monte Carlo event generators, particularly PYTHIA, have been quite successful at describing LEP physics and also p-p phenomenology. This surprise element...
We explore Glauber Monte Carlo predictions for the planned ultra-relativistic 16O+16O and p+16O collisions, as well as for collisions of 16O on heavy targets [1]. In particular, we present specific collective flow measures which are approximately independent on the hydrodynamic response of the system, such as the ratios of eccentricities obtained from cumulants with different numbers of...
Hydrodynamic expansion and jet quenching are responsible for the production of low and high transverse-momentum ($p_T$) particle in heavy-ion collisions, respectively. However, it is still a challenge to simultaneously describe hadron nuclear modification factor $R_{AA}$ and elliptic flow $v_2$, especially in the intermediate $p_T$ region of 2<$p_T$<10 GeV/c. In this talk, besides...
Several important processes and analyses at the LHC are sensitive to higher-order perturbative corrections beyond what can currently be calculated at fixed order. One important class of large logarithmic corrections are so-called high-energy logarithms which appear when the centre-of-mass energy of a QCD collision is much larger than the transverse momenta of the observed jets.
The effect of...
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 and CMS experiments have developed a broad search program for DM candidates, including resonance searches for the mediator which would couple DM to the...
The polarization properties of $\Lambda$ and $\overline{\Lambda}$ have received increasing attention over the last years due to the possibility to
link this observable to the properties of the medium produced in relativistic heavy-ion collisions. For semi-central collisions, the matter density profile in the transverse plane develops an angular momentum, which can be quantified in terms of...
LHCb is a spectrometer that covers the forward region of proton-proton collisions, corresponding to the pseudo-rapidity range 2<eta<5. In this unique phase space, LHCb can perform tests of perturbative and non-perturbative QCD models, by studying the production of heavy flavor quarks, like charm and top quarks. In this context the production of a Z boson in association with a c-jet can be...
The main goal of the STAR experiment is to study the properties of QCD matter at extreme conditions, high temperature and/or high density, by colliding heavy ions at ultra-relativistic speed. The yields and particle ratios of strange hadrons provide important information about the particle production mechanisms in these collisions. The RHIC Beam Energy Scan program covers a wide range of...
The world’s largest sample of J/ψ 1.3 billion events accumulated at the BESIII dector offers a unique opportunity to study light meson decays. In recent years the BESIII experiment has made significant progresses in eta/eta' decays, including observation of eta'->pi+pi- mu+mu-, search for the rare decays of eta’4pi0 and eta’gam gam eta as well as the search for CP violation in eta’pi+pi-...
There have been recent updates to the three global PDF fits (CT, MSHT and NNPDF), all using significant amounts of data from the LHC, in addition to the non-LHC data sets that formed the core of previous iterations. Given the impact of the LHC data on the global PDF fits, and the impact that the new PDFs will have on physics comparisons at the LHC, it is crucial to perform a benchmarking among...
Semi-visible jets arise in strongly interacting dark sectors, where parton evolution includes dark sector emissions, resulting in jets overlapping with missing transverse momentum. The implementation of semi-visible jets is done using the Pythia Hidden valley module to duplicate the dark sector showering. In this work, several jet substructure observables have been examined to compare...
Measurements of jet profiles in high-energy collisions are sensitive probes of QCD parton splitting and showering. Precise understanding of the jet structures are essential for setting the baseline not only for nuclear modification of jets in heavy-ion collisions, but also for possible semi-soft cold QCD effects such as multi-parton interactions (MPI) that may modify jets in high-multiplicity...
The general concept of the $z$-scaling based on fundamental principles of self-similarity, locality, and fractality of strange and non-strange particle production in $p+p$ and $Au+Au$ systems at high energies is discussed. We present new results of analysis of $K^0_S-$ meson spectra in $Au+Au$ collisions obtained by the STAR Collaboration at RHIC using the $z$-scaling approach. The analyzed...
Our study is aimed at the high multiplicity region where the series of collective phenomena are predicted. This region of multiplicity is unique. We have succeeded to descend on topological cross sections three orders down and receive the evidence the formation of a pion (Bose-Einstein) condensate. Almost half of the kinetic energy of an incident proton turns into secondary pions. For...
Forward-backward (FB) correlations of produced particles between symmetrically located pseudorapidity ($\eta$) intervals play an important role in understanding the dynamics of multiparticle interactions and their hadronization in different collision systems like hadronic or nuclear. Various experiments including CERN Super Proton Synchrotron (SPS) & the Large Hadron Collider (LHC), the...
A transformation of collision data into new data structures that are suitable for machine learning techniques is an importation direction for future research. This study shows the usability of rapidity-mass matrices (RMM) for general event classification and for anomaly detection in collision data. The proposed standardization of the input feature space can simplify searches for signatures...
Two-particle transverse momentum correlation functions are a powerful technique for understanding the dynamics of relativistic heavy-ion collisions. Among these, the transverse momentum correlator $G_{2}\left(\Delta\eta,\Delta\varphi\right)$ is of particular interest for its potential sensitivity to the shear viscosity per unit of entropy density $\eta/s$ of the quark-gluon plasma formed in...
Various measurements on long-range correlation among produced particles from small collision systems indicate that there are collective flow phenomena in these systems. Previously, PHENIX published elliptic and triangular flow results in $p$+Au, $d$+Au, and $^{3}$He+Au collisions of different initial geometry which are well described by hydrodynamics. A new independent analysis has been...
A primary aim of current nuclear science research at RHIC and the LHC is to delineate the normal and anomalous transport properties of the QGP produced in ion-ion collisions. I will show that the comprehensive RHIC and LHC data sets for different beam energies and collision systems in tandem with novel correlators and scaling functions provide unique insight into the transport properties of...
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...
Rapidity-odd directed flow ($v_{1}$) of identified hadrons ($\pi^{\pm}$, $K^{\pm}$, $p$, $\overline{p}$, $\phi$, $\Lambda$, $\overline{\Lambda}$, $\overline{\Xi}^{+}$, $\Omega^{-}$ and $\overline{\Omega}^{+}$) in Au+Au collisions at $\sqrt{s_{NN}}$ = 7.7, 14.5, 27, 54.4 and 200 GeV using the AMPT model with the new quark coalescence is analyzed. A new method to test the Coalescence Sum Rule...
To learn about the mechanism of particle production and phase changes from quarks to hadrons, fluctuations of observables from experiments are studied. Scaling of the observables from these experiments can reveal the properties of the system created, as it expands from quark-gluon plasma phase to hadronic phase. One of such techniques is to study the scaling behaviour of the normalized...
This talk gives an overview of the latest measurements of collective behavior in a variety of collision systems with the ATLAS detector at the LHC, including pp collisions at 13 TeV, Xe+Xe collisions at 5.44 TeV, and Pb+Pb collisions at 5.02 TeV. These include measurements of vn-[pT] correlations in Xe+Xe and Pb+Pb, which carry important information about the initial-state geometry of the...
The structure of hadrons relevant for deep-inelastic scattering are completely characterised by the Compton amplitude. As a physical amplitude, the Compton tensor is parameterised by structure functions and it naturally includes all target mass corrections and higher twist effects at a fixed virtuality, $Q^2$.
In this talk, I will be highlighting QCDSF/UKQCD Collaboration's recent...
We consider the production of electroweak Z or $W^\pm$ bosons associated with $J/\psi$ mesons at the LHC conditions. Our attention is focused on new partonic subprocesses which yet have never been considered in the literature, namely, the charmed or strange quark excitation subprocesses followed by the charmed quark fragmentation $c\to J/\psi+c$. Additionally we take into account the effects...
Basis light-front quantization (BLFQ) provides a nonperturbative framework for solving relativistic many-body bound state problems in quantum field theories. We report our recent progress in applying BLFQ to illuminating structure of the meson and the baryon. We present our results on the meson spectra and other observables such as electromagnetic form factors, PDFs, GPDs and TMDs of the pion...
B anomalies attract a lot of attention in the last few years. In the charged current caused ratios of the taounic semileptonic B decays to D() and the muonic one indicate deviations from the standard model prediction. In the case of flavour changing neutral current processes ratio of muonic and electronic in B to K() transitions and similar transitions of b to s l+ l- in variety of decays...
We consider a method for determining the QCD strong coupling constant
using fits of perturbative predictions for event shape averages to data
collected at the LEP, PETRA, PEP and TRISTAN colliders. To obtain highest
accuracy predictions we use a combination of perturbative ${\cal{O}}(\alpha_{S}^{3})$
calculations and estimations of the ${\cal{O}}(\alpha_{S}^{4})$ perturbative...
Calculations of Drell-Yan production at next-to-leading (NLO) order have been combined with transverse Momentum Dependent (TMD) distributions obtained with the Parton Branching (PB). For the first time, the predictions show a remarkable agreement with DY measurements across a wide range of DY mass and center of mass energies, from experiments like NuSea, R209, Phenix, CMS and ATLAS....
Abstract: Invariant inclusive single-particle/jet cross sections in p–p collisions can be factorized in terms of two separable pT dependences, a [pT-√s] sector and an [xR-pT-√s] sector. We have analyzed data from ATLAS, CMS and LHCb to explore various s-dependent attributes and other systematics of inclusive jet, photon and single particle productions. Approximate power laws in √s, pT and xR,...
In deeply inelastic lepton-nucleus scattering, hadron-nucleus and heavy-ion collisions, multiple scatterings of energetic partons in the nuclear medium lead to a broadening of the average jet transverse momentum. This jet broadening phenomenon offers a useful tool for probing the properties of nuclear media, including the quark-gluon plasma formed in high-energy heavy-ion collisions. Many...
Despite being the overwhelming majority of events produced in
hadron or heavy ion collisions, minimum bias events do not enjoy a robust
first-principles theoretical description as their dynamics are dominated
by low-energy quantum chromodynamics. In this talk, I will present a novel
expansion scheme of the cross section for minimum bias events in the large
number of detected...
Recent developments of the model of quantized helical QCD string
are presented, notably the baryon production. An overview
of the experimental evidence and the progress in
the model implementation in Monte-Carlo simulation are discussed.
Quark-gluon plasma (QGP) was discovered in heavy ion collisions at Relativistic Heavy Ion Collider. Later the formation of the QGP was confirmed by the Large Hadron Collider at much higher energies. Although QGP existence might be beyond doubt, its properties nowadays are the subject of detailed systematic study.
Strange quarks are absent in the colliding heavy ions and can only be...
Recent results of soft and small-x QCD measurements with the CMS experiment, such as minimum bias/underlying event physics, Double Parton Scattering and forward jet production.
Photon-photon fusion is a rare process at hadron and ion colliders. It is particularly interesting as a remarkably clean interaction with little (if any) remnant activity from the interacting particles. In this talk we present the status of photon-photon fusion measurements at the ATLAS detector. We present differential measurements of the light-by-light scattering process, γγ → γγ, in...
The light-front holography or light-front AdS/QCD is defined as a connection between light-front QCD and the description of hadronic modes on AdS spacetime. This relation, inspired in the AdS/CFT correspondence, has shown improvements in analytic solutions in the hadron physics regime.
We are motivated by the light-front AdS/QCD prediction on a general form of two particle bound state wave...
Multiparticle correlations measurements in even the smallest collision systems are consistent with predictions from viscous relativistic hydrodynamics calculations. However, these hydrodynamics calculations use a continuum extrapolated---i.e. infinite volume---equation of state. For the modest temperature probed in these small collisions, the controlling dimensionless product of the...
We present a new release of the NNPDF family of global analyses of the proton's parton distribution functions: NNPDF4.0. It includes a wealth of new experimental data from HERA and the LHC, from dijet cross-sections and isolated photons to single-top and top-quark pair differential distributions. The NNPDF4.0 methodology benefits from improved machine learning algorithms, in particular...
Lattice QCD (LQCD) is a theoretical non-perturbative approach for the study of QCD dynamics numerically from first principles. LQCD is widely used for hadron structure calculations and is becoming a reliable tool, striving for control of various sources of systematic uncertainties. Parton distribution functions (PDFs) have a central role in understanding hadron structure and have been...
The quark-gluon dynamics manifests itself in a set of non-perturbative functions describing all possible spin-spin and spin-orbit correlations. The Transverse Momentum Dependent parton distributions (TMDs) and Generalized Parton Distributions (GPDs) carry information not only on the longitudinal but also on the transverse momentum and position of partons, providing rich and direct...
The Pierre Auger Observatory is the largest facility in the world to observe ultra-high-energy cosmic rays. It has a hybrid detection technique which combines the observation of the longitudinal development of the shower of secondary particles produced in the atmosphere by the cosmic primary and the measurement of particles at ground. This has allowed the Auger Collaboration to produce results...
Next generation neutrino experiments will push the limits in our understanding of astroparticle physics in the neutrino sector to energies orders of magnitude higher than the current state-of-the-art high-energy neutrino experiment, IceCube. These experiments will use neutrinos to tell us about the most extreme environments in the universe, while simultaneously leveraging these extreme...
The Giant Radio Array for Neutrino Detection (GRAND) is designed to detect ultra-high-energy cosmic particles — specially neutrinos, cosmic rays and gamma-rays using radio antennas. On its final design, the radio array will contain 200,000 antennas and cover a total area of 200,000 km$^{2}$ split in $\sim$20 montainous sites spread worldwide. The detection strategy is based on the coherent...
Charged pions, which obviously carry no baryon number, possess, however, a nontrivial baryonic structure, stemming from the isospin breaking with the up and down quark mass splitting and the EM effects. We obtain estimates for the corresponding pion baryonic (vector isoscalar) form factor in two ways: from simple constituent quark models on one hand, and from vector meson dominance model fits...
Medium-induced gluon radiation is known to be an important tool to extract the properties of the QGP created in heavy-ion collisions. I will use a recent approach to evaluate the full in-medium gluon emission spectrum, including the resummation of all multiple scatterings, to analyze the validity of the usually employed analytical approximations. More specifically, by using this all-order...
We consider the hadronization of the deconfined matter arising in high-energy particle collisions, based on the quark-hadron duality concept. The number of generated hadrons is shown to be entirely determined by the exact non-equilibrium Green's functions of partons in the deconfined matter and the vertex function governed by the probability of the confinement-deconfinement phase...
Briefly after the Big Bang, the early universe was in a high temperature and high density environment. In order to recreate this state of matter in the laboratory, mini bangs are created by colliding heavy ions at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory and subsequently at the Large Hadron Collider (LHC) at CERN. In this talk I shall be covering on the...
Jet substructure, defined by observables constructed from the distribution of constituents within a jet, provides the versatility to tailor observables to specific regions of QCD radiation phase space. This flexibility provides exciting new opportunities to study jet quenching in heavy-ion collisions and to
ultimately help reveal the nature of the quark-gluon plasma. In this talk, we focus on...
Recently, event shape observables such as transverse spherocity ($S_{0}$), has been studied successfully in small collision systems at the LHC as a tool to separate jetty and isotropic events. In our work, we have performed an extensive study of charged particles' azimuthal anisotropy in heavy-ion collisions as a function of $S_{0}$ for the first time using a multi-phase transport (AMPT)...
The Belle II experiment at the SuperKEKB energy-asymmetric $e^+ e^-$ collider is an upgrade of the B factory facility at KEK in Tsukuba, Japan. The experiment began operation in 2019 and aims to record a factor of 50 times more data than its predecessor. Belle II is uniquely capable of studying the so-called "XYZ" particles: heavy exotic hadrons consisting of more than three quarks. First...
We study tetraquark states of all $qq\bar q\bar q$, $qc\bar q \bar c$, $sc\bar q \bar c$ and $cc\bar c \bar c$ ($q=u,d$ quark) quark configurations and all S-wave tetraquark masses are evaluated in a constituent quark model where the Cornell-like potential and one-gluon exchange spin-spin coupling are employed.
All model parameters are predetermined by comparing the theoretical and...
In this talk, we present the production measurements of $\Lambda_{\rm c}^{+}$, $\Xi^{0,+}_{\rm c}$, $\Sigma^{0,++}_{\rm c}$ and the first measurement of $\Omega_{\rm c}^{0}$ baryon performed with the ALICE detector at the midrapidity in pp collisions at $\sqrt s=$ 5.02 and 13 TeV. Recent results show that the baryon-to-meson ratios are significantly higher than those measured in $\rm...
Hypernuclei are bound nuclear systems of nucleons and hyperons. As such, hypernuclei are correlated hyperon-baryon systems and therefore provide direct access to study the hyperon$-$nucleon (Y-N) interaction. Production of hypernuclei in heavy-ion collisions provides an experimental avenue for studying the Y-N interaction. $\Lambda$ hypernuclei, such as $^3_{\Lambda}H$ and $^4_{\Lambda}H$,...
NA61/SHINE is a fixed-target experiment at CERN Super Proton Synchrotron which goal is to explore the phase diagram of strongly interacting matter. A two-dimensional scan of this diagram is performed by varying the beam momentum (13A-150(8)A GeV/c) and the system size (p+p, Be+Be, Ar+Sc, Xe+La, Pb+Pb). The motivations of this measurements are the study of the properties of the onset of...
The measurement of exclusive $e^+e^-$ to hadrons processes is a significant part of the physics program of $BABAR$ experiment, aimed to improve the calculation of the hadronic contribution to the muon $g−2$ and to study the intermediate dynamics of the processes. We present the most recent results obtained by using the full data set of about 470 $fb^{−1}$ collected by the BABAR detector at the...
The study of medium-induced modifications to the substructure of inclusive charged jets indicates a redistribution of energy inside the jet cone and provides insight into the energy loss mechanisms of jets in the medium. The in-medium modification to two jet shape observables i.e., the differential jet shape ($\rho$(r)) and the angularity (g) in the most central Pb−Pb collisions at 2.76TeV has...
The particle momentum anisotropy ($v_n$) produced in relativistic nuclear collisions is considered to be a response of the initial geometry or the spatial anisotropy $\epsilon_n$ of the system formed in these collisions. The linear correlation between $\epsilon_n$ and $v_n$ quantifies the efficiency at which the initial spatial eccentricity is converted to final momentum anisotropy in...
NA61/SHINE (SPS Heavy Ion and Neutrino Experiment) is a fixed-target experiment at the CERN Super Proton Synchrotron. One of its research projects is the systematic measurement of hadron production in proton+proton, proton+nucleus and nucleus+nucleus interactions. These studies are performed in particular to study the predicted signals of the onset of deconfinement and search for the critical...
We study hidden-charm pentaquarks in the molecule picture of charmed baryon and anticharm meson in the approach of quark model and group theory. The strong decay of $P_c(4312)$, $P_c(4440)$, and $P_c(4457)$ are calculated for all 18 quark configurations and 47 states. It is found that all the possible states for Pc can decay through the $NJ/\psi$ channel and $N\eta_c$ channel for J=1/2, while...
In relativistic heavy ion collisions the number of participant nucleons fluctuates event-by-event due to the fluctuations in the nucleon positions around the mean nuclear density profile. This asymmetry causes a shift in the center-of-mass rapidity of the participant zone and is known as longitudinal asymmetry. We have studied the effect of the longitudinal asymmetry on charged particle...
Spectra of dilepton pairs in ultraperipheral nuclear collisions
are calculated. It is shown that production of low-mass e+e- pairs is enhanced due to the Sommerfeld-Gamow-Sakharov (SGS) factor. This effect is especially strong near the threshold of creation of unbound pairs with low masses in the two-photon fusion. Coulomb attraction of the non-relativistic components of such pairs may lead...
In high energy scattering, multiproduction process is unique in its relevance to total cross section an in its global property such as rapidity distribution, etc. If there is hard interactions, the jet rate and structure is a good arena of perturbative chromodynamics. However, once any specific hadron is considered, The property and structure of the hadron must make sense while the global...
The existence of topological solutions of the Standard Model field equations has been established since the 70ies. In Quantum Chromodynamics, these "Instanton transitions" are known to play a fundamental role in the long-distance behaviour of the theory, yet direct experimental evidence of these phenomena is still lacking. This raises the question of whether these processes could be observed...
Studies of identical-particle correlations started with radio astronomy and later with correlations of identical pions in proton-antiproton collisions. These measurements, more generally called femtoscopy, can be used to investigate the space-time dimensions of the region from which the particles are emitted. However the method applied to high energy collisions is sensitive not only to quantum...
In an extension to our previous work where we established that the intermittency-type fluctuations as outlined by Bialas and Peschanski in the 1980s is present at √s = 7 TeV, the analysis is continued to include more energies from Run 1 data from the CMS collaboration at CERN. A preliminary look into how the slope parameters in the bin-averaged scaled factorial moments vary with collision...
Oscillations in modified combinants (C j s) have been of interest to multiparticle production mechanisms since the 1990s. Recently, there has been a discussion on how such oscillations can be reproduced by compounding a binomial distribution with a negative binomial distribution. In this work, we explore a stochastic branching model based on a simple interaction term Aφ ∗ φ for partons and...
We present a discussion on recent progress in high energy diffraction from the perspective of AdS/CFT, through which a unified treatment for both perturbative and non-perturbative Pomeron emerges. By working with unitary irreducible representation of conformal group, a frame is provided in extending AdS/CFT to both forward and near-forward scattering. We present an analysis involving an exact...
The production of $W/Z$-bosons in association with jets is an important test of perturbative QCD predictions and also yields information about the parton distribution functions (PDFs) of the proton. The latest results of differential cross-section measurements for Z-boson production in association with jets (including heavy flavour) from the ATLAS experiment at the LHC will be presented. The...
Recent measurements of tree-level $b\to c\ell\nu$ and loop-level $b\to s \ell^{+}\ell^{-}$ decays show an intriguing and consistent pattern of tensions between measured observables and Standard Model predictions. These tensions are referred to collectively as the flavour anomalies. This talk outlines the current experimental status of the flavour anomalies, with particular focus on...
B anomalies attract a lot of attention in the last few years. The charged current caused ratios of the taounic semileptonic B decays to D() and the muonic one indicate deviations from the standard model prediction. In the case of flavor changing neutral current processes ratio of muonic and electronic in B to K() transitions and similar transitions of b to s l+ l- in various decays again,...
The Belle II experiment at the SuperKEKB energy-asymmetric e+e− collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The target luminosity of the machine is $6\times10^{35}$ cm$^{−2}$s$^{−1}$ and the Belle II experiment aims to record 50 ab$^{−1}$ of data, a factor of 50 more than its predecessor. With this data set, Belle II will be able to measure the...
The pre-equilibrium stage of quark-gluon plasma remains one of the major sources of uncertainty in studies of heavy ion collisions, which became a prominent research problem in heavy ion community. Major efforts regarding this problem are made in low-$p_\perp$ sector. We here instead propose [1] to utilize high-$p_{\perp}$ particles energy loss, as a complementary tool, to elucidate these...
The comparison of experimental data and theoretical predictions is crucial for our understanding of the mechanisms for interactions and particle production in hadron collisions, both at the Large Hadron Collider (LHC) and at the Relativistic Heavy-Ion Collider (RHIC). In order to help with that task, several tools were created. The Rivet (Robust Independent Validation of Experiment and Theory)...
The ALICE experiment at the LHC is designed to study the hot and dense medium produced in ultra-relativistic heavy-ion collisions. Light-flavour hadrons, such as pions, kaons, protons, strange hadrons, resonances and (hyper)nuclei are optimal probes to characterise the bulk properties of the medium. This is achieved by studying particle hadro-chemistry, with a focus on strangeness production,...
The study of hadronic jet substructure has become a burning topic in recent years, bringing to a high request for designing precise observable to understand it. A novel observable, called the "Jet Colour Ring", aims at constructing a colour tagger, able to discriminate the decay of a colour-singlet into two jets from a two-jet background in a different colour configuration. The Jet Colour Ring...
An important observable for studying partonic energy loss in high energy nucleus-nucleus collisions is the jet fragmentation function. Detailed investigation of low momentum (10-60 GeV) jet fragmentation functions may complement previous studies by providing more information on energy loss. The main difficulty in studying low momentum jets in heavy ion collisions is the presence of a...
Keynote talk, covering state-of-the-art lattice computations and impacts on g-2 and flavour-universality anomalies.
Recently, jet measurements in DIS events close to Born kinematics have been proposed as a new probe to study transverse-momentum-dependent (TMD) PDFs, TMD fragmentation functions, and TMD evolution. We report measurements of lepton-jet momentum imbalance and hadron-in-jet correlations in high-$Q^2$ DIS events collected with the H1 detector at HERA. The jets are reconstructed with the kT...
A first measurement of the 1-jettiness event shape observable in neutral-current deep-inelastic electron-proton scattering is presented. The 1-jettiness observable 𝜏1𝑏 is defined such that it is equivalent to the thrust observable in the Breit frame, following momentum conservation. The data were taken with the H1 detector at the HERA ep collider at a center-of-mass energy of 319 GeV in the...
We present our recent NNLO calculation of t-channel single-top-quark production and decay that resolves a disagreement between two previous calculations whose size at the inclusive level was comparable to the NNLO correction itself, and was even larger differentially. Moving beyond those comparisons, we have included b-quark tagging to allow for comparison with experiment, and added the...
We apply the formalism developed earlier [1, 2] for studying transverse momentum dependent parton distribution functions (TMDs) at small Bjorken $x$ to construct the small-$x$ asymptotics of the quark Sivers function. First, we explicitly construct the complete fundamental “polarized Wilson line” operator to sub-sub-eikonal order. We then express the quark Sivers function in terms of...
In past many studies are done on cosmic ray which are said to be messengers of universe but no one yet think to study the effects when there is a meteor showers. It opens a new window to study more about the universe or allows us to see the universe in a different way. Most of stratosphere conditions can be created in laboratories like Temperature, Pressure, humidity and even some radiations...
Collective phenomena in heavy-ion collisions are very sensitive to initial geometry including nuclei deformation effects. Recent hydrodynamic calculations and preliminary data by the STAR Collaboration show such deformation effects can be probed by studying the correlation between event-wise average transverse momentum $[p_T]$ and harmonic flow $v_n$. In particular, due to prolate shape of the...
The everyday practice of physicists is to a large extent determined by the scientific problems they are confronted with. The conceptual analysis of scientific problems and how they change, therefore, may allow for a fine-grained investigation of the development of a scientific discipline. In this talk I discuss what constitutes a scientific problem, what its elements are and how they change. I...
The ALICE experiment studies the physics of strongly interacting matter, focusing on the properties of the Quark-Gluon Plasma (QGP). The relative production of strange hadrons with respect to non-strange hadrons in heavy-ion collisions was historically considered as one of the signatures of QGP formation. Recent results in proton-proton (pp) and proton-lead (p-Pb) collisions have revealed an...
Multi-particle correlations have been compelling tools to probe the properties of the Quark-Gluon Plasma (QGP) created in the ultra-relativistic heavy-ion collisions and the search for the QGP in small collision systems at the LHC. However, only very few of them are available and studied in theoretical calculations and experimental measurements, while the rest are generally very interesting,...
Polarization of Lambda hyperons, produced in relativistic heavy-ion collisions, has been discovered in 2017 by STAR experiment in the Beam-Energy Scan program at RHIC. The trends in the global Lambda polarization are in good agreement with hydrodynamic models. However, the transverse momentum dependence of polarization components in the out-of-plane direction and beam direction does not agree...
Local density fluctuation near the QCD critical point has been suggested to exhibit a power-law behavior which can be probed by an intermittency analysis on scaled factorial moment (SFM) in relativistic heavy-ion collisions.
In this talk, I will firstly review recent heavy-ion experimental results on the intermittency measurement from STAR, NA49 and NA61 collaborations. These results are...
In the relativistic heavy-ion collisions the mean transverse momentum ($[p_{T}]$) and anisotropic flow ($v_n$, n=2,3) have been found to be tightly correlated with the size and initial geometry eccentricity of the produced fireball, respectively. It provides a novel tool to image the deformation of the atomic nuclei at extremely short time scale ($<10^{-24}$s).
In this talk, we present...
In the RHIC Beam Energy Scan program, gold nuclei are collided with different collision energies in the range from few to 62.4 GeV. The goals of the program are to explore the onset of QGP creation, locate the critical point of QCD and study dense baryon matter.
In this talk, we report on the first application of 3D Monte Carlo Glauber (GLISSANDO2) and TrENTO p=0 initial states for 3D...
Droplets of quark-gluon plasma produced in heavy-ion collisions rapidly evolve expanding and cooling. During considerable part of this dynamics the system can be described within relativistic hydrodynamics. Recently, there were some attempts to include effects of the medium motion to the jet energy loss and jet modification calculations in a variety of models. Here we will present the first...
In scattering experiments, a multitude of hadronic states was observed
already in the 50s and 60s of the last century. In order to explain
their abundance, a systematic approach was taken to search for an
underlying structure. Quantum chromodynamics was developed as a
theoretical description of these strongly interacting particles,
explaining the interactions between quarks and gluons, of...
Heavy quarks (charm and beauty) are produced at the initial stages of the relativistic hadronic collisions in hard scattering processes. The study of heavy-flavor production provides a stringent test to perturbative Quantum Chromo-Dynamics (pQCD) calculations in proton-proton (pp) collisions and can help in disentangling cold nuclear matter (CNM) effects in proton-lead (p--Pb) collisions....
We describe an analysis comparing the $p\bar{p}$ elastic cross section as measured by the D0 Collaboration at a center-of-mass energy of 1.96~TeV to that in $pp$ collisions as measured by the TOTEM Collaboration at 2.76, 7, 8, and 13 TeV using a model-independent approach. The TOTEM cross sections, extrapolated to a center-of-mass energy of $\sqrt{s} =$ 1.96 TeV, are compared with the D0...
Recently, a statistically significant signal for the observation of the odderon has been published in EPJ C, that reported an Odderon signal of at least 6.26 sigma, based on a scaling analysis of the differential cross-sections of elastic pp and pbarp scattering in the TeV energy range [1]. The D0 and TOTEM collaborations reported an at least 5.2 sigma Odderon signal from a comparison of the...
We present recent BFKL phenomenological studies for several novel probes that have been proposed for the LHC and different collider environments. Since that the typical BFKL observables at the LHC are the azimuthal angle $\phi$ correlations of tagged particles in the final state, which are separated in rapidity, a specific attention has been drawn to the behaviour of the so-called azimuthal...
We use a recently proposed formalism which includes both small and large x gluons of a target nucleus (or proton) to calculate the photon-parton production cross section. This allows one to investigate azimuthal angular correlations between the produced photon and parton from low to high p_t, as well as the forward-backward rapidity correlations between the them.
Two-particle transverse momentum correlator is a powerful technique for understanding the dynamics of relativistic heavy-ion collisions. Among these, the transverse momentum correlator $G_{2}\left(\Delta\eta,\Delta\varphi\right)$ is of particular interest for its potential sensitivity to the shear viscosity per entropy density $\eta/s$ of the quark-gluon plasma formed in heavy-ion...
In the past years, significant progress has happened in high-energy nuclear physics models. A more robust and quantitative picture has replaced the qualitative descriptions of heavy nuclei collisions in the earlier days, enabling us to have a clearer picture of different stages of a heavy-ion collision. These models typically have $O(10)$ free parameters that are tuned by Bayesian analysis in...
In the past years, significant progress has happened in high-energy nuclear physics models. A more robust and quantitative picture has replaced the qualitative descriptions of heavy nuclei collisions in the earlier days, enabling us to have a clearer picture of different stages of a heavy-ion collision. These models typically have $O(10)$ free parameters that are tuned by Bayesian analysis in...
Two-particle transverse momentum correlator is a powerful technique for understanding the dynamics of relativistic heavy-ion collisions. Among these, the transverse momentum correlator $G_{2}\left(\Delta\eta,\Delta\varphi\right)$ is of particular interest for its potential sensitivity to the shear viscosity per entropy density $\eta/s$ of the quark-gluon plasma formed in heavy-ion...
The light-front holography or light-front AdS/QCD is defined as a connection between light-front QCD and the description of hadronic modes on AdS spacetime. This relation, inspired in the AdS/CFT correspondence, has shown improvements in analytic solutions in the hadron physics regime.
We are motivated by the light-front AdS/QCD prediction on a general form of two particle bound state wave...
In the RHIC Beam Energy Scan program, gold nuclei are collided with different collision energies in the range from few to 62.4 GeV. The goals of the program are to explore the onset of QGP creation, locate the critical point of QCD and study dense baryon matter.
In this talk, we report on the first application of 3D Monte Carlo Glauber (GLISSANDO2) and TrENTO p=0 initial states for 3D...
An important observable for studying partonic energy loss in high energy nucleus-nucleus collisions is the jet fragmentation function. Detailed investigation of low momentum (10-60 GeV) jet fragmentation functions may complement previous studies by providing more information on energy loss. The main difficulty in studying low momentum jets in heavy ion collisions is the presence of a...
In past many studies are done on cosmic ray which are said to be messengers of universe but no one yet think to study the effects when there is a meteor showers. It opens a new window to study more about the universe or allows us to see the universe in a different way. Most of stratosphere conditions can be created in laboratories like Temperature, Pressure, humidity and even some radiations...
Medium-induced gluon radiation is known to be an important tool to extract the properties of the QGP created in heavy-ion collisions. I will use a recent approach to evaluate the full in-medium gluon emission spectrum, including the resummation of all multiple scatterings, to analyze the validity of the usually employed analytical approximations. More specifically, by using this all-order...
Multiparticle correlations measurements in even the smallest collision systems are consistent with predictions from viscous relativistic hydrodynamics calculations. However, these hydrodynamics calculations use a continuum extrapolated---i.e. infinite volume---equation of state. For the modest temperature probed in these small collisions, the controlling dimensionless product of the...
The study of hadronic jet substructure has become a burning topic in recent years, bringing to a high request for designing precise observable to understand it. A novel observable, called the "Jet Colour Ring", aims at constructing a colour tagger, able to discriminate the decay of a colour-singlet into two jets from a two-jet background in a different colour configuration. The Jet Colour Ring...
Charged pions, which obviously carry no baryon number, possess, however, a nontrivial baryonic structure, stemming from the isospin breaking with the up and down quark mass splitting and the EM effects. We obtain estimates for the corresponding pion baryonic (vector isoscalar) form factor in two ways: from simple constituent quark models on one hand, and from vector meson dominance model fits...
Semi-visible jets arise in strongly interacting dark sectors, where parton evolution includes dark sector emissions, resulting in jets overlapping with missing transverse momentum. The implementation of semi-visible jets is done using the Pythia Hidden valley module to duplicate the dark sector showering. In this work, several jet substructure observables have been examined to compare...
Droplets of quark-gluon plasma produced in heavy-ion collisions rapidly evolve expanding and cooling. During considerable part of this dynamics the system can be described within relativistic hydrodynamics. Recently, there were some attempts to include effects of the medium motion to the jet energy loss and jet modification calculations in a variety of models. Here we will present the first...
Collective phenomena in heavy-ion collisions are very sensitive to initial geometry including nuclei deformation effects. Recent hydrodynamic calculations and preliminary data by the STAR Collaboration show such deformation effects can be probed by studying the correlation between event-wise average transverse momentum $[p_T]$ and harmonic flow $v_n$. In particular, due to prolate shape of the...
There have been recent updates to the three global PDF fits (CT, MSHT and NNPDF), all using significant amounts of data from the LHC, in addition to the non-LHC data sets that formed the core of previous iterations. Given the impact of the LHC data on the global PDF fits, and the impact that the new PDFs will have on physics comparisons at the LHC, it is crucial to perform a benchmarking among...
We present a Monte Carlo based analysis of the combined world data on polarized lepton-nucleon deep-inelastic scattering at small Bjorken $x$ within the polarized quark dipole formalism. We show for the first time that double-spin asymmetries at $x<0.1$ can be successfully described using only small-$x$ evolution derived from first-principles QCD, allowing predictions to be made for the $g_1$...
We present a complete set of transverse momentum dependent (TMD) parton densities with the Parton Branching (PB) method. TMDs extracted at LO and NLO from HERA DIS data with different number of active flavours. We also present the first TMD density of the photon, covering a wide range in $x$, $k_t$ and $\mu$. The advantage of PB method is that extracted densities automatically contain soft...
One of the main goals of RHIC beam energy scan (BES) program is to search for the signatures of QCD critical point in heavy-ion collisions. It is predicted that the local density fluctuations near the critical point exhibit power-law scaling, which can be probed with an intermittency analysis of the scaled factorial moments, $F_{q}(M)$, for charged particles. The power-law behavior of $q^{th}$...
We investigate the validity of the limiting-fragmentation hypothesis and its centrality dependence in relativistic heavy-ion collisions at energies reached at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC).
A phenomenological analysis of Au-Au and Pb-Pb collisions within a three-source relativistic diffusion model (RDM) is performed at $\sqrt{s_{NN}}=19.6,...
This talk gives an overview of the latest hard process measurements in heavy ion collision systems with the ATLAS detector at the LHC, utilizing the high statistics 5.02 TeV Pb+Pb data collected in 2018. These include multiple measurements of jet production and structure, which probe the dynamics of the hot, dense Quark-Gluon Plasma formed in relativistic nucleus-nucleus collisions;...
The physics of jet quenching, a generic denomination for the modifications of jets produced in the dense environment of an ultra-relativistic nucleus-nucleus collision, represents one of the main tools at our disposal to experimentally probe the quark-gluon plasma. In this talk, I will discuss recent theoretical breakthrough in our understanding of this physical phenomenon, within the...
Interactions of high-$p_{\rm{T}}$ partons with quark-gluon plasma (QGP) result in jet quenching, which is manifest by the suppression of high-$p_{\rm{T}}$ jet yields and the modification of jet substructure and di-jet acoplanarity distributions. Several jet quenching phenomena can be measured precisely over a wide range of jet $p_{\rm{T}}$ using semi-inclusive distributions of charged jets...
Jet Substructure measurements will be presented with some emphasis on inclusive observables in various specific phase space regions or for different signal processes. Measurements dealing with jet tagging techniques, including the use of multivariate techniques, their performance comparisons and specific use cases like top tagging will also be discussed.
