QCD with chiral(axial) chemical potential will be reconstructed with the help of effective low energy Lagrangians and different models of NJL type. Their thermodynamic properties will be confronted to lattice predictions. Possible signatures of chiral imbalance will be guessed.
We will present new methods to compute the parton distributions, the proton charge radius and the neutron electric dipole moment. We will demonstrate the applicability of our methods using twisted mass fermion configurations and compare to the results of other lattice QCD collaborations. Finally we will discuss future directions and perspectives for baryon structure studies within lattice QCD.
The overarching science challenges for the coming decade are to discover the meaning of confinement, its relationship to dynamical chiral symmetry breaking (DCSB) - the origin of visible mass - and the connection between these two, key emergent phenomena. There is strong evidence to suggest that they are intimately connected with the appearance of momentum-dependent masses for gluons and...
The HEP Inquiry learning resources created over the last three-four years by the Inspiring Science Education and Go-lab European outreach projects will be reviewed. The resources are mostly addressed to high school students and the purpose is to ignite their interest on science. To that end, science exhibitions as well as science fairs (like the ones organized by this conference) try to reach...
We present a status report of our current knowledge of parton distribution functions in the nucleon, including the flavor and spin decomposition, using the latest information from experiments ranging from lower-energy fixed target facilities to the highest-energy hadron colliders.
Chirality of neutrinos modifies the conventional hydrodynamic behavior at the macroscopic scale and leads to anomalous transport phenomena in neutrino matter. We argue that such chiral transport of neutrinos should play important roles in the evolution of core-collapse supernovae, and, in particular, leads to the possible inverse energy cascade from small to large scales, which may be relevant...
We discuss the use of light-front field theory in the descriptions of hadrons.
In particular, we clarify the confusion in the prevailing notion of the equivalence between the infinite momentum frame and the light-front dynamics and the advantage of
the light-front dynamics in hadron physics. As an application, we present our recent work on the flavor asymmetry in the proton sea and identify...
X
Heavy quarks (charm and beauty) are interesting probes to study the Quark-Gluon Plasma (QGP) in high-energy heavy-ion collisions, since they are produced in initial hard partonic scattering processes on a short time scale and experience the whole evolution of the medium. They are expected to traverse the QCD medium, interacting with its constituents and losing energy through radiative and...
Rare electroweak penguin processes provide a rich platform to search for new physics. Some deviations have recently been found between the rate and angular distribution of these processes measured by the LHCb experiment and theoretical predictions. In addition, LHCb has seen hints of lepton universality breaking in these rare processes. This talk will review these measurements and put them in...
Talk based on paper by
G. Triantaphyllou, EJTP 13, No. 35 (2016) 115–144
http://www.ejtp.com/articles/ejtpv13i35p115.pdf
Kinetic theory is one of the main dynamical frameworks to model ultrarelativistic heavy-ion collisions at RHIC and the LHC. For example, it has been used to study i) thermalization during the early partonic stage of the collision, ii) hadronic mixture evolution in late stages of the reaction, and more recently also iii) proper inclusion of nonthermal phase space density corrections for...
We present results of simulations of the RQCD Collaboration on open charm states, including a scattering analysis of scalar and axialvector $D_s$ mesons near the physical pion mass, utilizing different spatial volumes. The spectra are obtained, using $N_f=2$ QCDSF and RQCD as well as $N_f=2+1$ CLS ensembles, employing non-perturbatively improved Wilson fermions. In the latter case,...
I review the theory of the search for new physics with rare flavour-changing processes, some of which may indicate departures from the Standard Model, with an emphasis on the Standard-Model predictions and their uncertainties. I will focus on semileptonic B decays, but will also discuss recent developments and prospects in K physics.
Dense matter in the core of neutron stars is strongly coupled and presents an enormous theoretical challenge. First-principle methods from QCD are currently known only for vanishing or asymptotically large densities, while phenomenological models are usually restricted to either nuclear or quark matter and/or contain many unknown parameters. I will discuss whether and how holographic methods...
This talk will review recent progress in using holography to learn lessons about heavy ion collisions. I will illustrate the use of holography for the earliest stage of HIC, before hydrodynamics applies, and also during the hydrodynamic evolution in order to describe the energy loss and shape evolution of jets traversing the hydrodynamic medium. Interesting results include the fast...
I will review recent results obtained within the Hamiltonian approach to QCD in Coulomb gauge at finite temperatures. The temperature is introduced by compactifying a spatial dimension. Results are presented for the chiral and dual quark condensate as well as for the Polyakov loop and the pressure
I will review recent lattice results on the meson and baryon spectrum with a focus on the determination of hadronic resonance masses and widths using a combined basis of single-hadron and hadron-hadron interpolating fields. I will emphasize how these mostly exploratory calculations differ from traditional lattice QCD spectrum calculations for states stable under QCD.
We present the inelastic scattering between $\gamma\gamma$ into/out of a strongly interacting EWSBS satisfying unitarity. The matrix elements $V_L V_L\to V_L V_L $, $V_L V_L \to hh$, $hh\to hh$, $V_L V_L \to \gamma \gamma$ and $hh \to \gamma \gamma$ are al computed to NLO in perturbation theory with the Nonlinear Effective Theory of the EWSBS (within the Equivalence Theorem).
Describing the...
The extraction of the $B \to K^*$ transition form factors from lattice data at (close to) physical pion masses is discussed. The possible mixing of $\pi K$ and $\eta K$ states is taken into account. Applying non-relativistic effective field theory in a finite volume, the two-channel analogue of the Lellouch-Luscher formula is reproduced. Due to the resonance nature of the $K^*$ , it is shown...
The LHC has found several anomalies in exclusive semileptonic b --> s mu mu decays with a global significance of more than 4 sigma. I will discuss the hadronic uncertainties entering the theoretical prediction for the relevant decays and present model-independent global fits of new physics to the data. The discrimination between high-scale new physics and low-energy QCD effects, as well as the...
We discuss the phenomenon of (inverse) magnetic catalysis for both the deconfinement and chiral transition. We discriminate between the hard and soft wall model, which we suitably generalize to include a magnetic field. Our findings show a critical deconfinement temperature going down, in contrast with the chiral restoration temperature growing with increasing magnetic field. This is at odds...
We analyze long-distance QCD effects in $B_{d,s}\to\ell^+\ell^-\gamma$ decays.
Taking into account photon emission from the $b$-quark loop, weak annihilation,
and Bremsstrahlung from leptons in the final state, we give predictions
for dilepton spectrum and various asymmetries in $B_{d, s}\to \ell^+\ell^-\gamma$ decays within the Standard Model.
A wealth of information on the properties of hadrons of both
theoretical and experimental interest can be provided by lattice
methods. This includes wavefunctions, their response to electromagnetic, weak
or beyond the Standard Model probes and their internal dynamics in ...
I will discuss recent advances in the perturbative description of the thermodynamic properties of cold unpaired quark matter. After presenting new results for the temperature dependence of the Equation of State (EoS), I will describe recent advances in determining the next four-loop term in the weak coupling expansion of the zero-temperature EoS. The potential implications of these results to...
By means of forward sum-rules for γγ and gg scattering we show that a spin-0 resonance with mass of the order of the TeV and a sizable γγ or gg partial width -of the order of a few GeV- must be accompanied by higher spin resonances with JR≥2 with similar properties, as expected in strongly coupled extensions of the Standard Model or, alternatively, in higher dimensional deconstructed duals....
N/A
Lattice QCD calculations with dynamical fermions are getting more and more precise in recent years. The uncertainties of lattice QCD results can be shrinked systematically. I will discuss lattice QCD calculations of weak matrix elements related to quark flavor anomalies in bottom quark decays.
We present the results of our recent calculations of the hadronic form factors for semileptonic decays of B mesons and the matrix elements of local operators contributing to neutral B and Bs meson mixing. From joint fits of the lattice results and the experimental data we are able to determine the magnitude of the CKM matrix elements Vub and Vcb, and also (with Vtb as an additional input) the...
In this talk, the latest results of searches for the standard model Higgs boson produced in association with a top quark-antiquark pair (ttH), where Higgs decays into photons, bottom quark-antiquark pair or leptons via WW, ZZ and tautau will be presented. The analyses have been performed using the 13 TeV pp collisions data recorded by the CMS experiment in 2015. The results are presented in...
We numerically solve 2+1D effective kinetic theory of weak coupling QCD under longitudinal
expansion relevant for early stages of heavy-ion collisions. We find agreement with viscous hydrodynamics and classical Yang-Mills simulations in the regimes where they are applicable. With a reasonable initial condition for the anisotropic system in the heavy ion collisions, we found that the system...
We will discuss the extraction of the axial, scalar and tensor charges using twisted mass fermions with simulations at a physical value of the u and quark mass. In addition, we will discuss the nucleon sigma-terms and compare the results obtained recently within lattice QCD.
The fermonic Green’s functions of QCD exhibit an unexpected property of `effective locality’, which is exact. In the strong coupling limit, at quenching and eikonal approximations, effective locality implies a dependence of non-perturbative fermonic Green’s functions on both $C_{2f}$ and $C_{3f}$ Casimir operators, that is, on the full algebraic content of the $SU(3)$ rank-2 color algebra....
Essential nonperturbative dynamical features of QCD are well captured in a semiclassical effective theory based on the extension of superconformal quantum mechanics to the light-front and its holographic embedding in a higher dimensional gravity theory. This new approach to hadron physics incorporates confinement, the appearance of a massless pion, and Regge spectroscopy consistent with...
We propose an astrophysical scenario in which hadronic stars and quark stars coexist. While hadronic stars would populate a branch of very compact objects (radii measurements indicate the existence of such configurations in some cases), quark stars would instead populate a branch of very massive stars (e.g. the two solar mass star PSR J1614-2230). The conversion process between a hadronic star...
The top quark is the heaviest known fundamental particle. As it is the only quark that decays before it hadronizes, this gives us the unique opportunity to probe the properties of bare quarks and to test perturbative QCD. This talk will focus on a few recent precision top quark measurements by the ATLAS Collaboration: fiducial top pair and single top production cross sections including...
We present a lattice QCD study of coupled-channel $D\pi$, $D\eta$ and $D_{s}\bar{K}$
scattering, as well single-channel $DK$ scattering. Our methodology allows us to determine precise finite volume spectra which we use to constrain scattering amplitudes as a function of energy. We interpret our results in terms of poles in the $S$-matrix and provide a measure of the coupling of each channel...
coupling constant, nonperturbative QCD parameter, dispersive model.
Beyond perturbation theory gauge-fixing becomes more involved due to the Gribov-Singer ambiguity: The appearance of additional gauge copies requires to define a procedure how to handle them. For the case of Landau gauge the structure and properties of these additional gauge copies will be investigated. Based on these properties new gauge conditions are constructed to account for these gauge...
We show that having at hand the analytic expression for the correlation functions allows one to study subtle effects related to isospin-breaking effects in the decay constants of heavy pseudoscalar and vector mesons. We obtain predictions for these effects in fD, fD, fB and fB mesons.
Meson electroproduction data play an important role in our understanding of hadron structure and the dynamics that bind the basic elements of nuclear physics. Pion and kaon form factors are of particular interest as they are connected to the Goldstone modes of chiral dynamical symmetry breaking. The last decade saw a dramatic improvement in precision of charged pion form factor data and new...
A precise understanding of low-energy pion-nucleon interactions is central for many areas in nuclear and hadronic physics, ranging from the scalar couplings of the nucleon to the long-range part of two-pion-exchange potentials and three-nucleon forces in Chiral Effective Field Theory. We present a calculation that combines the general principles of analyticity, unitarity, and crossing symmetry...
I will present recent progress on the lattice investigation of a nearly conformal gauge theory, SU(3) with 2 flavors of sextet fermions, that may realize a composite Higgs impostor scenario.
Soft particle production in ultrarelativistic heavy-ion collisions is surprisingly well described by the "flow paradigm" which states that particles are emitted independently, according to a one-particle probability distribution that fluctuates event to event. I review some consequences of this flow paradigm and show how it can be used to relate correlations of different orders.
If the Higgs boson discovered at the LHC is not exactly the one predicted
by the Standard Model the theory becomes strongly coupled at high energy
and vector boson scattering violates unitarity in the TeV range. This can
be regularised by the introduction of new heavy resonances. These
resonances may also couple to quark pairs and can be searched for in their
decay to vector or Higgs...
The aspects of mesons containing a single heavy quark are governed by the spin symmetry $SU(2)_s$ of the heavy quark and the chiral symmetry $SU(3)_L\times SU(3)_R$ of the light quarks. Incorporating both approximate symmetries in a single framework was achieved by defining the heavy meson chiral perturbation theory (HMChPT).
The masses of D and B mesons are analysed within this effective...
Bernhard Ketzer [Bernhard.Ketzer@cern.ch]
I will present recent progress in the calculation of nucleon resonances using the framework of Dyson-Schwinger and Bethe-Salpeter equations. The resulting mass spectra are obtained both from the three-body bound-state equation as well as its quark-diquark approximation starting from the level of QCD's propagators and vertices. I will outline how a better understanding of these n-point...
A combination is presented of all inclusive deep inelastic cross sections previously published by the H1 and ZEUS collaborations at HERA for neutral and charged current ep scattering for zero beam polarisation. The data were taken at proton beam energies of
920, 820, 575 and 460 GeV and an electron beam energy of 27.5 GeV. The data correspond to an integrated luminosity of about 1 fb −1 and...
I will review some of the recent progress in determining the infrared behavior of two color gauge theory with fermions in fundamental or adjoint representation of the gauge group. Particular focus will be given to the theory with six Dirac fermions in the fundamental reptesentation.
The WZ boson pair production at 13 TeV is measured using the ATLAS detector. Leptonic decays of the W and Z bosons to electrons and muons are considered using 2015 and 2016 data. The differential cross-section as a function of jet multiplicity, the Z-boson pT and the transverse mass of the WZ system are also measured along with the charge-dependent W+Z and W-Z cross-sections and their ratio....
Anisotropic flow studies play a crucial role in improving our understanding of the behaviour and the nature of matter created in collisions of heavy ions. The different flow harmonics ($v_n$) harmonics for identified particles can be used to constrain the initial conditions and the value of shear viscosity over entropy density ratio. These studies allow also to reveal the role of the hadronic...
Measurements of the cross sections of the production of pairs of electroweak gauge bosons at the LHC constitute stringent tests of the electroweak sector of the Standard Model and provide a model-independent means to search for new physics at the TeV scale.
The ATLAS collaboration has measured inclusive and differential cross sections of the production of ZZ pairs in final states with four...
We have analysed the phenomenological dependence of the spin independent ($F_1^{p,n}$ and $F_2^{p,n}$) and the spin dependent ($g_1^{p,n}$) structure functions of the nucleon on the the Bjorken scaling variable $x$ using the unpolarized distribution functions of the quarks $q(x)$ and the polarized distribution functions of the quarks $\Delta q(x)$ respectively. The chiral constituent quark...
I will review the conditions and properties of the anomalous triangle singularity (ATS) in the transition matrix elements. For certain processes, the ATS condition can be fulfilled and will produce measureable effects in physical observables. In particular, when the ATS threshold is located within the physical regime, it may produce threshold enhancements which can mix with pole structures...
General aspects of the application of hydrodynamics in theoretical description of heavy-ion collisions are shortly reviewed with the emphasis on the following issues: fluid variables, the form of hydrodynamic expansion, early thermalization vs. early hydrodynamization scenario, the use of the realistic equation of state, incorporation of the phase transition and pre-equilibrium flow, free...
We investigate the spectrum of the SU(2) gauge theory with
Nf = 2 flavors of fermions in the fundamental representation, in the
continuum, using Lattice simulations.
This model provides a minimal template which has been used for
different strongly coupled extensions of the Standard Model ranging from
composite (Goldstone) Higgs models to intriguing types of dark
matter candidates, such...
The mass of the bottom quark can be determined with high precision from moments of the pair-production cross section $\sigma(e^+ e^- \to b \bar{b})$ near threshold. We present the first complete NNNLO determination from non-relativistic sum rules, obtaining a bottom-quark mass of $m_b^\text{PS}(2\,\text{GeV}) = 4.532^{+0.013}_{-0.039}\,\text{GeV}$ in the potential-subtracted scheme. For the...
All the information about a quantum field theory is contained in the n-point functions. Once the n-point functions are computed they can be used in a next step to calculate hadron properties e.g. via the Bethe-Salpeter approach. On the level of three-point functions especially the three-gluon and quark-gluon vertices are of interest. The three-gluon vertex captures the property of...
We consider the predictions and estimate systematically all theoretical uncertainties
of pion-photon transition form factor using the light-cone sum rules at low-mid
momenta-transfer.
The properties of the QCD axion are strictly related to the
dependence of the theory on the topological parameter theta.
We will present a determination of the topological properties of QCD for
temperatures up to around 600MeV, obtained by lattice QCD simulations
with 2+1 flavors and physical quark masses. Numerical results for
the topological susceptibility, when compared to instanton...
Yang-Mills theory and 2-flavour QCD are investigated with the functional renormalisation group equation in the vacuum. Starting from the perturbative parameters of QCD as only input, the effective action is calculated in a vertex expansion. The focus is put on the properties of the corresponding 1PI correlations functions as well as the relation between confinement and chiral symmetry breaking.
Although the main use of lattice QCD computation is to provide non-perturbative calculation of low-energy physical quantities, it can also be used to calculate short-distance quantities. By matching thus calculated short-distance current correlators to corresponding perturbative calculations one can obtain the parameters appearing in the perturbation theory, such as the strong coupling...
We study the effect of magnetic field $B$ on the critical temperature $T_{c}$ of the confinement-deconfinement phase transition in hard-wall AdS/QCD, and holographic duals of flavored and unflavored $\mathcal{N}=4$ super-Yang Mills theories on $\mathbb{R}^3\times \rm S^1$. For all of the holographic models, we find that $T_{c}(B)$ decreases with increasing magnetic field $B\ll T^2$, consistent...
Observation of novel long-range collective phenomena in high-multiplicity pp and pA collisions at the LHC has opened up new opportunities of exploring QCD dynamics in a high-density environment. Major progress in experimental and theoretical community has been made in recent years to unravel the physical origin of the observed phenomena. In this talk, I will review the experimental results...
The low energy (below ~2 GeV) pi-eta channel interaction amplitude becomes an object of interest mainly because of the search for exotic mesons in just beginning to collect data detector GlueX in Jefferson Lab. Finding and interpretation of expected weak signals from these states require a comparison with a very accurate amplitude containing standard (q-bar q) states i.e. a0(980) and a0(1450)....
The determination of quark masses from lattice QCD simulations requires a non-perturbative renormalization procedure and subsequent scale evolution to high energies, where a conversion to the commonly used $\overline{\rm MS}$ scheme can be safely established. We present our results for the non-perturbative running of renormalized quark masses in $N_{\rm f}=3$ QCD between the electroweak and a...
Dyson-Schwinger equations are an established, powerful non-perturbative tool for QCD. In the Hamiltonian formulation of a quantum field theory they can be used to perform variational calculations with wave functionals going beyond the Gaussian approximation. The various $n$-point functions, needed in expectation values of observables like the Hamilton operator, can be thus expressed in terms...
Hadrons carrying heavy quarks, i.e. charm or bottom, are important probes of the hot and dense medium created in relativistic heavy-ion collisions. Heavy quark-antiquark pairs are mainly produced in initial hard scattering processes of partons. While some of the produced pairs form bound quarkonia, the vast majority hadronize into open heavy flavor particles. RHIC experiments carry out a...
The NA62 experiment at CERN collected a large sample of charged kaon decays with a highly efficient trigger for decays into electrons in 2007. The kaon beam represents a source of tagged neutral pion decays in vacuum. A measurement of the electromagnetic transition form factor slope of the neutral pion in the time-like region from ~1 million fully reconstructed pi0 Dalitz decay is presented....
The study of the couplings of the Higgs boson and of the top quark plays a preeminent role at the LHC, and could unveil the first signs of new physics. I will discuss the interplay of direct and indirect probes of certain classes of top and Higgs couplings. Including constraints from collider observables, precision electroweak tests, flavor physics, and electric dipole moments (EDMs), I will...
Results of a sophisticated approach to a comprehensive meson phenomenology within the
rainbow-ladder truncated Dyson-Schwinger--Bethe-Salpeter equation framework are presented
and discussed.
The exotic and non-exotic light and heavy quarkonium mass spectrum in the
spin-0 and spin-1 channel, as well as for tensor mesons is evaluated.
Quasi-exotic counterparts of exotic quarkonia in the...
Anisotropic hydrodynamics is a reformulation of relativistic viscous hydrodynamics which allows one to more reliably describe non-equilibrium fluid dynamics. This is accomplished by taking into account inherent local-rest-frame momentum-space anisotropies at leading order. Through comparisons with recently obtained exact solutions to the Boltzmann equation, it has been shown that anisotropic...
The strong CP problem of QCD can be solved via the Peccei-Quinn mechanism. The resulting pseudo-Goldstone bosons, the axions are natural candidates for dark matter. In order to quantitatively understand axion dark matter production two important QCD inputs are required: the equation of state and the topological susceptibility at high temperatures. We determine these quantities and use them to...
In this talk we present the Two-hadron saturation (THS) scenario for the PVV correlator and apply it to two important processes of the low energy hadron physics: the Dalitz decay of $\pi^0$ and $\pi^0\to e^+e^-$. We briefly summarize experimental and theoretical results on the rare decay $\pi^0\to e^+e^-$. The notorious $3.3\,\sigma$ discrepancy between the SM prediction and the experimental...
I review recent work on the Roy-Steiner equations for pion-nucleon scattering. This allows to extract the S- and P-wave phase shifts in the low-energy and subtreshold regions and a precise extraction of the much debated pion-nucleon sigma term. I also discuss these results in view of recent sigma term determination from various lattice QCD collaborations.
Inclusive observables, insensitive to hadronization effects, are adequately described with the short-distance Operator Product Expansion. Higher-order perturbative calculations and improved experimental data sets make possible performing precise tests of QCD and accurate deteminations of the strong coupling at the NNNLO. The present status will be reviewed.
The discrepancy between the measured Lamb shift in muonic hydrogen and expectations from electron-proton scattering and hydrogen spectroscopy has become known as the proton radius puzzle, whose most "mundane" resolution requires a $\sim 5 \sigma$ shift in the value of the Rydberg constant. I review the status of spectroscopic and scattering measurements, recent theoretical developments, and...
There are a number of high profile, high impact experiments planned to probe the limits of the Standard Model through precision measurements at low energies in nuclear physics environments. These experiments include searches for: direct dark matter detection through the elastic recoil of large nuclei; CP-violation manifested in permanent electric dipole moments in nucleons and nuclei;...
Presented at Confinement XII
Precision measurements of flavour observables can provide powerful tests of many extensions of the Standard Model. I will present a review of recent heavy flavour results, focussing on places where tensions have started to appear between experimental measurements and Standard Model predictions. The talk will discuss possible explanations for these tensions and highlight areas where theoretical...
The concept of Generalized Parton Distributions promises an understanding of the generation of the charge, spin, and energy-momentum structure of hadrons by their fundamental constituents, quarks and gluons. Forthcoming measurements with unprecedented accuracy at Jefferson Lab and at CERN will presumably challenge our quantitative description of the three-dimensional structure of hadrons. To...
It is based on https://arxiv.org/abs/1511.03868 as well as work which should appear soon.
I discuss calculations of the Polyakov loop and of Polyakov loop correlators using lattice gauge theory.
I briefly review recent calculations (since Conf. 2014) of the Polyakov loop and static quark correlators.
I cover in detail results in QCD with 2+1 flavors and almost physical quark masses using the highly improved staggered quark action (HISQ).
I examine the short- and long-distance...
Electromagnetic E1 (and M1) multipole transitions have been studied since the early days of hadron spectroscopy because they allow to access heavy quarkonium states which are below open-flavour threshold. Moreover, they are interesting by themselves because they are an important tool to check particular regions of the hadrons' wave function and thus to determine their internal structure and...
Due to the non-Abelian nature of QCD and the existence of the 3-gluon coupling, the wavefunction of a high energy hadron at small-x is dominated by gluons (with x the longitudinal momentum fraction of a parton). The occupation numbers for these soft gluons increase rapidly with decreasing x and eventually saturate to their maximal allowed value, in a region where the coupling is still weak....
We study the relation between quark confinement and chiral symmetry breaking in QCD.
First, we analytically derive some relations of the Polyakov loop or its fluctuations with Dirac eigenmodes for Wilson, clover and Domain-Wall fermions in QCD [1-3]. For these quantities related to confinement, the contribution from the low-lying Dirac eigenmodes is found to be negligibly small, while the...
The Symmetry Energy is a fundamental ingredient of the nuclear matter Equation Of State.
The elliptic-flow ratio of neutrons with respect to protons or light complex particles in
reactions of heavy-ions at pre-relativistic energies has been proposed as an observable sensitive to the strength of the Symmetry Energy at supra-saturation densities.
The results obtained from the existing...
Belle, a general-purpose detector operated at the KEKB electron-positron
B-factory at KEK, Japan, collected the world largest integrated luminosity
at the peak of the $\Upsilon(4S)$ meson as well as in a scan of the
center-of-mass energy range from 10.63 to 11.05 GeV.
We describe recent results on various bottomonium states studied -
mass and width measurements of the $\Upsilon(5S)$ and...
The chiral magnetic effect (CME) is the generation of electrical current induced by chirality imbalance in the presence of magnetic field. It is a macroscopic manifestation of the quantum chiral anomaly in systems possessing charged chiral fermions. In quark-gluon plasma containing nearly massless quarks, the chirality imbalance is sourced by the topological transitions. In condensed matter...
In order to obtain a better understanding of QCD as well as possible strongly coupled extensions of the Standard Model it is important that we reliably can calculate anomalous dimensions of certain composite operators at fixed points. We show how to consistently calculate the mass anomalous dimension order by order in perturbation theory in a scheme independent manner. We compare our...
HADES at SIS18 is currently the only experiment studying properties of strongly interacting matter by means of rare and penetrating probes using proton and heavy ion beams in a few AGeV energy range. The study of system size dependence has been recently completed with Au+Au collisions at 1.23 AGeV. The measurements provide a results on kaons, strange resonances, including the first at such...
A full understanding of the spacetime evolution of the QCD matter created in a heavy ion collision requires understanding the properties of the initial stages. In the weak coupling picture these are dominated by classical gluon fields, whose properties can also be studied via the scattering of dilute probes off a high energy hadron or nucleus. A particular challenge is understanding small...
The magnitude of axial U(1) symmetry breaking is believed to affect the nature of phase transition in QCD with two light quark flavors. I review the recent studies on the fate of axial U(1) in finite temperature QCD using lattice techniques. Most of them investigate the eigenvalue spectrum of the fermion Dirac operator in QCD. The current understanding from majority of these studies is that...
In the last few years we have had a major advance on our understanding
of the motion of partons inside nuclei. This has been achieved recognizing the role
of rapidity divergences in the factorization theorems for transverse momentum dependent cross sections (for Drell-Yan, Semi-inclusive DIS, ee-> 2 hadrons), using effective field theories, performing higher order calculations in...
Numerical recovering of the spectrum and wave function of a two-body fermionic relativistic potential system.
Estimation in this framework of the widths and branching ratios of some heavy mesons radiative decays.
We will present recent results regarding chiral symmetry restoration and other hadronic properties at finite temperature. In particular, we will discuss the interpretation of the temperature dependence of lattice screening masses through Ward identities relating pseudoscalar susceptibilities and quark condensates. Such identities are derived for two and three flavours and studied within the...
The AMADEUS experiment deals with the investigation of the low-energy kaon-nuclei hadronic interaction at the DAΦNE collider at LNF-INFN, which is fundamental to solve longstanding questions in the non-perturbative strangeness QCD sector. AMADEUS step 0 consisted in the reanalysis of 2004/2005 KLOE data, exploiting $K^−$ absorptions in H, ${}^4$He, ${}^9$Be and ${}^{12}$C, leading to the first...
The combination of multiple particle identification systems along with the excellent tracking capabilities makes ALICE a unique tool for the measurement of light flavor hadron production over a broad transverse momentum ($p_{\rm T}$) range.
The production of $\pi^{\pm}$, $\mathrm{K}^{\pm}$, ${\rm K}^{0}_{S}$, $\rm p$,
$\rm\overline{p}$, $\Lambda$, $\bar{\Lambda}$, $\Xi^-$,...
We use non-linear field transformations for non-relativistic fields to implement Poincare invariance in low energy effective theories for QCD. In these transformations we include all terms allowed by the explicit symmetries of the effective theory, but exploit the freedom to remove some of them through field redefinitions. By requiring the invariance of the Lagrangian under these...
A gobal effort is ongoing in the study of transverse-momentum dependent structure functions and in generalised parton distribution functions. Both are linked to orbital angular momentum of quarks and gluons in the nucleon. Recent results from various experiments will be discussed.
I will start by an introduction to holographic QCD, concentrating on bottom-up models where the backreaction of quarks to gluon dynamics is fully included (V-QCD models). The physics of theta angle and axial anomaly can be consistently included in such models. At small quark mass the models agree with effective field theory. I show how the Gell-Mann-Oakes-Renner relation for the mass of the...
The study of lattice gauge theories with Monte Carlo simulations is hindered by the infamous sign problem that appears under certain circumstances, in particular at non-zero chemical potential. So far, there is no universal method to overcome this problem. However, recent years brought a new class of non-perturbative Hamiltonian techniques named tensor networks, where the sign problem is...
We derive an analytical expression for the chromopolarizability of bottomonium states using the framework of potential nonrelativistic QCD. Next, using the QCD trace anomaly we obtain the two-pion production amplitude for the chromopolarizability operator and match the result to a chiral effective field theory for bottomonium states and pions as degrees of freedom. In this chiral effective...
We discuss the importance of initial state effects with regard to the theoretical understanding of long range azimuthal correlations observed in high-multiplicity p + p and p + A collisions at RHIC and the LHC. Starting with a brief overview of different effects, we perform a systematic comparison of initial state calculations with experimental data and briefly discuss progress towards...
At zero temperature nucleons and their parity partners have non-degenerate
masses due to spontaneous breaking of chiral symmetry.
However, chiral symmetry is expected to be restored at sufficiently high temperature,
in particular when going from the hadronic to the quark-gluon plasma (QGP) phase,
implying that the parity partners should become degenerate.
We study the nucleon (spin 1/2)...
The protein folding problem, it has been claimed, is one of the
most important problems in science; Dirac stated that the problem
of life is one in theoretical physics. We argue that gauge invariance
can be employed, to develop an energy function that describes the dynamics
of a folding protein, with sub-atomic precision.
The in-medium modification of hadron properties is the main field of study for the strangeness sector in the non-perturbative low-energy region of QCD.
The behaviour of strange hadrons at extreme densities are of capital importance for the description of the nuclear equation of state and the evaluation of the strangeness component in the core of the neutron stars.
The study of...
A novel approach to identify the geometrical (anti)clusters formed by the Polyakov loops of the same sign and to study their properties in the lattice SU(2) gluodynamics is developed. The (anti)cluster size distributions are analyzed for the lattice coupling constant $\beta$=[2.3115; 3]. The found distributions are similar to the ones existing in 2- and 3-dimensional Ising systems [1]. Using...
Identified hadron spectra are considered to be sensitive to transport properties of strongly interacting matter produced in high-energy nucleus-nucleus collisions.
π0 and η mesons in ALICE are identified via their two-photon decays by using calorimeters and the central tracking system. In the latter, photons are measured via their conversion to electron-positron pairs on the material of the...
While QCD is the theory underlying hadronic physics, much of our intuition about hadronic states has been developed in the context of the constituent quark model. Exotic states—ones that cannot be described in the simplest version of the quark models with mesons as a quark-antiquark state and baryons as a three quark state—are important since they clarify the limitation of the quark model as...
The non-perturbative nature of quantum chromodynamics (QCD) has historically left a gap in our understanding of the connection between the fundamental theory of the strong interactions and the rich structure of experimentally observed phenomena. For the simplest properties of stable hadrons, this is now circumvented by utilizing lattice QCD (LQCD). In this talk I outline a path towards a...
The anomalous magnetic moment of the muon $(g-2)_\mu$ has been measured and computed to very high precision of about 0.5 ppm. For more than a decade, a discrepancy has persisted between experiment and Standard Model prediction, now of about $3\sigma$. The main uncertainty of the theory prediction is due to strong interaction effects. With the expected improvement of the input for hadronic...
QCD thermodynamics in strong magnetic fields shows some unexpected features like inverse catalysis, which have been revealed mainly through lattice studies. Many effective descriptions, on the other hand, use Landau levels or approximate the system by just the lowest Landau level (LLL). Analyzing lattice configurations we ask whether such a picture is justified. We find the LLL to be separated...
The LHCb experiment is designed to study the decays and properties of heavy flavoured hadrons produced in the forward region from pp collisions at the CERN Large Hadron Collider. It has recorded the world’s largest data sample of beauty and charm hadrons, enabling precise studies into the production and decay of such particles. $\eta_c$ production has been studied in B decays and in prompt...
Heavy quarkonium presents a unique observable for the study of the quark-gluon plasma in relativistic heavy-ion collisions. While Bottomonium is expected to act as a test particle traversing the medium in the collision center, recent measurements of finite $J/\psi$ flow by the ALICE collaboration hint at the participation of the charm quarks in the collectivity of the bulk.
Here we present...
Based on arXiv:1410.6448, arXiv:1512.06445 and ongoing works
We analyze the first measurement of $\eta_c$
production, performed by the LHCb Collaboration, in
the nonrelativistic-QCD (NRQCD) factorization framework
at next-to-leading order (NLO) in the
strong-coupling constant $\alpha_s$ and the relative velocity v
of the bound quarks including the feeddown
from $h_c$ mesons. Converting the long-distance matrix elements (LDM
Es) extracted by...
The method of QCD sum rules is based on the extraction of hadron observables (decay constants, form factors, etc) from the correlation functions of the appropriate quark currents. Because of the properties of the correlation functions containing the exotic multiquark (i.e. four-quark, five-quark) currents, the contribution of the exotic multiquark hadrons to these correlation functions emerge...
The Muon g-2 Experiment at Fermilab aims to measure the anomalous magnetic moment of the muon to a precision of 140 parts per billion. This four-fold improvement over the previous Brookhaven E821 measurement provides significant insight into the tantalizing 3.5 standard deviation discrepancy between measurement and the Standard Model prediction
The measurement of the anomalous magnetic moment...
We study $N_f=2$ lattice QCD with improved Wilson fermions at imaginary chemical potential $\mu_I.$ Simulations are made in the deconfinement phase at few values of $\mu_I/T$ to study Roberge-Weiss phase transitions at $\mu_I/T = \pm \pi/3$ and $\pi$. We measure spectrum of overlap Dirac operator in background of equilibrium configurations with variable $\mu_I/T$. Numerical evidence is...
Numerical Lattice QCD calculations are necessarily performed in a finite volume and with Euclidean time. For scattering and transition amplitudes these constraints have important consequences. In particular, it is not possible to directly access such amplitudes from numerically determined Euclidean correlators. In the past decades, great progress has been made to overcome this limitation by...
We explain the approach to thermal equilibrium of strongly coupled non-conformal plasmas using the AdS/CFT correspondence. The theories we study are the holographic duals to Einstein gravity coupled to a scalar with an exponential potential. The coefficient in the exponent, X, is the parameter that controls the deviation from the conformally invariant case. For these models we obtain analytic...
The modification of charmonium and bottomonium production in heavy ion collisions can provide information about the properties of the QGP, including the color screening length. But heavy quarkonia production can be modified by effects that precede QGP formation, as well as by effects that occur after hadronization. This requires that we study quarkonia formation in p+A collisions as well as...
The dispersive approach to QCD, which extends the applicability range of
perturbation theory towards the infrared domain, is applied to the study
of the hadronic vacuum polarization function and related quantities. This
approach merges the intrinsically nonperturbative constraints, which
originate in the kinematic restrictions on the relevant physical
processes, with corresponding...
The Qweak experiment, which ran for two and a half years at Jefferson Lab,
will precisely determine the weak charge of the proton by measuring the
parity-violating asymmetry in elastic e-p scattering at 1.1 GeV using a
longitudinally polarized electron beam and a liquid hydrogen target at a
low momentum transfer of $Q^2 = 0.025 \left(\textrm{GeV/c} \right)^2$. The
weak charge of the...
We show how the increase in the Instanton-dyon density can explain both Confinement and Chiral symmetry breaking. We simulate an ensemble of 64 interacting Instanton-dyons for 2 colors and 0 or 2 quark flavors. We find that at low temperatures, the high density of dyons prefer a symmetric density, which leads to the confining value of the Polyakov Loop. At the same time the Chiral condensate...
Since the first heavy-ion collisions which date back to thirty years ago, quarkonium is considered one among the most important probes of the formation of a plasma of quarks and gluons.
Quarkonium production is, in fact, expected to be strongly modified by the creation of a hot medium. On one side, quarkonium yields are suppressed, due to the Debye screening, with respect to those measured in...
Using the AdS/CFT correspondence, phenomenological models based on five-dimensional Einstein-Dilaton gravity can be constructed which give a realistic description of several non-perturbative properties of Yang-Mills theory at thermal equilibrium. These models can also be used to describe time-dependent and out-of-equilibrium processes, and to compute observables related to heavy quark...
A review of familiar results of the three-point Green functions of currents in the odd-intrinsic parity sector of QCD is presented. Such Green functions include very well-known examples of $VVP, VAS$ or $AAP$ correlators. We also present new results for $VVA$ and $AAA$ Green functions that have not yet been studied extensively in the literature before, more importantly with a phenomenological...
In the previous decade, the topic of the nucleon's nonperturbative or $\it{intrinsic}$ charm content has enjoyed something of a renaissance, largely motivated by theoretical developments involving quark modelers and PDF-fitters. In this talk I will briefly describe the importance of intrinsic charm to various issues in high-energy phenomenology, and survey recent progress in constraining its...
We calculate the neutron electric dipole moment within the framework of lattice QCD. In particular we
analyze configurations produced with $N_f=2+1+1$ twisted mass fermions with light quark mass which
corresponds to pion mass of 370 MeV. We do so by extracting the $CP$-odd form factor $F_3$ at the limit of
zero momentum transfer and at small values of the $\theta$ vacuum angle. The zero...
The renormalization group procedure for effective particles (RGPEP) has been
developed during the last years as a non-perturbative tool for constructing
bound-states in quantum field theories [1]. It stems from the similarity
renormalization group procedure (SRG) [2] and introduces the concept of effective
particles, which differ from the point-like canonical, bare ones by
having a finite...
We explore the ground state energy of pseudoscalar charged and neutral mesons as a function of external magnetic field in SU(3) lattice gauge theory. We calculate the dipole magnetic polarizabilities and hyperpolarizabilities of charged and neutral pseudoscalar pi and K mesons. It was found that the magnetic polarizability of charged pion agrees with the experimental prediction of COMPASS...
Current experiments aim at measuring parameters of Standard Model to an unprecedented accuracy, and as a consequence require theoretical calculations of radiative corrections that match that precision. The so-called dispersion corrections, or hadronic box corrections represent one of the main limitations of the reach of modern experiments in determining SM parameters and constraining the New...
Heavy quarks, i.e. charm and beauty, are produced primarily in the initial, hard partonic scatterings in hadronic collisions.
In pp collisions, their production is well described by perturbative QCD due to their large mass.
In heavy-ion collisions, heavy quarks propagate through and interact with the hot and dense QCD matter.
Therefore, measurements of heavy-flavour production provide...
The Quantum Chromodynamics (QCD) coupling, αs, is not a physical observable of the theory since it depends on conventions related to the renormalization procedure. We introduce a definition of the QCD coupling, denoted by αˆs, whose running is explicitly renormalization scheme invariant. The scheme dependence of the new coupling αˆs is parameterized by a single parameter C, related to...
The
dilepton invariant mass spectra and branching ratios of the single and double Dalitz decays
$\mathcal{P}\to\ell^{+}\ell^{-}\gamma$ and $\mathcal{P}\to\ell^{+}\ell^{-}\ell^{+}\ell^{-}$
($\mathcal{P}=\pi^{0}, \eta, \eta^{\prime}$; $\ell=e$ or $\mu$) are predicted by means of a
data-driven model-independent approach based on the use of rational approximants applied to
$\pi^{0}, \eta$...
The confinement and the gribov ambiguity are two non-perturbative phenomena of great importance in QCD. Abelian dominance, a signature to the confinement, is mostly studied in Maximal abelian gauge which is Abelian projection. The Gribov ambiguity exists in various gauges. Algebraic gauges are more likely to be ambiguity free but are not compatible with the boundary conditions i.e.,the...
Experimental measurements of muonic hydrogen bound states have recently started to take place and provide a powerful setting in which to study the properties of QCD. We profit of the power of effective field theories (EFTs) to provide a theoretical setting in which to study muonic hydrogen in a model independent fashion. In particular, we compute expressions for the Lamb shift and the...
Studies of multi-baryon systems present a formidable challenge to lattice QCD.
The H-dibaryon represents the simplest multi-baryon system and yet in the current lattice calculations at unphysical quark masses no conclusive results can be seen regarding its binding energy.
One of the contributing factors could be the inability to reliably extract the spectrum of states on the lattice.
Using...
We compute the QGP suppression of $\Upsilon(1s)$, $\Upsilon(2s)$, $\Upsilon(3s)$, $\chi_{b1}$, and $\chi_{b2}$ states in \mbox{$\sqrt{s_{NN}}=2.76$ TeV} Pb-Pb collisions. Using the suppression of each of these states, we estimate the inclusive $R_{AA}$ for the $\Upsilon(1s)$ and $\Upsilon(2s)$ states as a function of $N_{\rm part}$, $y$, and $p_T$ including the effect of excited state feed...
- Introduction
- Thermal Sum Rule for Charmonium and Charmed Beauty Vertex
- Numerical Analysis and Discussion
Hadron physics
We present a first-principles study of anomaly induced transport phenomena by performing real- time lattice simulations with dynamical fermions coupled simultaneously to non-Abelian SU(Nc) and Abelian U(1) gauge fields. We investigate the behavior of vector and axial currents
during a sphaleron transition in the presence of an external magnetic field, and demonstrate how the interplay of the...
Model parameter free investigations of Yang-Mills theory and quenched QCD in the vacuum are presented as a necessary prerequisitve for corresponding investigations of the QCD phase structure with the functional renormalisation group equation. Preliminary results for Yang-Mills theory at finite temperature are discussed. Finally, a phenomenological application of the vacuum results to the...
We calculate the potential between static quarks in the fundamental representation of the F4 exceptional gauge group using domain structures of the thick center vortex model. As non-trivial center elements are absent, the asymptotic string tension is lost while an intermediate linear potential is observed. SU(3) is a subgroup of F4. Investigating the decomposition of the 26 dimensional...
Electromagnetic processes are known to be a good source of information on the meson inner structure. Analysis of these processes turned out to be particularly fruitful in case of scalar mesons which emerge eg. in the phi(1020) radiative decays in both \pi\pi and \pi\eta channels.
Photoproduction of isoscalar and isovector scalar resonances can be treated as a complementary source of...
We report on the coupling of an external $t\bar t$ state to a strongly interacting EWSBS. We exploit perturbation theory in the small $M_t/\sqrt{s}$ quantity, whereas the EWSBS is taken as strongly interacting. We use a modified version of the IAM unitarization procedure to model such a strongly interacting regime. The scattering matrix elements $V_L V_L \to V_L V_L$, $V_L V_L \to hh$, $hh\to...
We present novel method for the organisation of events. The method is based on comparing event-by-event histograms of a chosen quantity $Q$ that is measured for each particle in every event. The events are organised in such a way that those with similar shape of the $Q$-histograms end-up placed close to each other.
We apply the method on histograms of azimuthal angle of the produced hadrons...
We derive three exact sum rules for the spectral function of the electromagnetic current channel at finite temperature, by using operator product expansion and hydrodynamics, focusing on zero spatial momentum case. We also discuss the possibility to use these sum rules to constrain and improve the functional form of the spectral function assumed in the lattice QCD analysis, and to evaluate the...
Minijets and jets are produced in large numbers in nuclear collisions at TeV energies, so that there are many of them in a single fireball. They deposit non-negligible amount of momentum and energy into the hydrodynamically expanding bulk and cause anisotropies of the expansion. Moreover, due to their multiple production in a single event the resulting anisotropies are correlated with the...
Within QCD, the light pseudoscalar mesons assume a twofold role: they may be described as quark–antiquark bound states but also have to be interpreted as the (almost) massless (pseudo) Goldstone bosons of the spontaneously broken chiral symmetries of QCD. The application of suitably adapted inversion techniques enables us to construct exact bound-state solutions to the Bethe–Salpeter equation...
We investigate the H-dibaryon (uuddss) in holographic QCD [1, 2].
Holographic QCD is derived from a QCD-equivalent D-brane system
in the superstring theory via the gauge/gravity correspondence.
In holographic QCD, all baryons appear as topological chiral solitons
of Nambu-Goldstone bosons and (axial) vector mesons [1, 2].
In this framework, the H-dibaryon can be described as an...
The presentation is based on these works
1) Heavy Quark Entropy shift: From the Hadron Resonance Gas to Power Corrections
By E. Megias, E. Ruiz Arriola, L.L. Salcedo.
arXiv:1605.04453 [hep-ph].
2) Heavy quark-antiquark free energy and thermodynamics of string-hadron avoided crossings
By E. Megias, E. Ruiz Arriola, L.L. Salcedo.
arXiv:1603.04642 [hep-ph].
3) Heavy ${\bar Q}Q$ free...
Holographic QCD is based on the AdS/CFT duality and offers new nonperturbative approaches to understand the strongly interacting regime of gauge theories. One of the primary questions in Quantum Chromodynamics is the clarification of the whole phase diagram of matter out of quarks and gluons as a function of temperature, baryon or quark chemical potential, and other external parameters.
We...
Based on the new fit of hadron yield ratios within the multicomponent hadron resonance gas model we have found several remarkable irregularities at chemical freeze-out. In particular, 121 hadron multiplicity ratios measured in the nucleus-nucleus collisions at AGS, SPS and RHIC energies were successfully described within the new formulation of HRGM with $\chi^2/dof \simeq 63.978/65 \simeq...
The magnetic susceptibility of the QCD vacuum is analyzed in the framework of a nonlocal
SU(3) Polyakov-Nambu-Jona-Lasinio model. We estimate the values of the u and s-quark tensor coefficients and magnetic susceptibilities and then we extend the analysis to finite temperature systems, comparing numerical results to those obtained in other theoretical approaches and in lattice QCD calculations.
The ATLAS reconstruction algorithm, in Run-II, has been improved and extended compared to the one used in Run-I. In this presentation, we will discuss the precise measurement of the muon reconstruction efficiency measured in pp collisions at sqrt(s)= 13 TeV in 2015 and 2016 using samples of J/ψ→μμ and Z→μμ decays. The reconstruction efficiency, transverse momentum resolution and momentum...
The lateral distribution of an atmospheric shower depends on the characteristics of the high energy interactions and the type of the primary particle. The influence of the primary particle in the secondary development of the shower into the atmosphere, is studied by analyzing the lateral distribution of electron and muon showers having as primary particle, proton, photon or iron nucleus.
This...
Super QCD Lagrangian and Feynman rules; self energies of quark, gluon, squark and gluino fields; 2-pt Green's functions of quark bilinears; lattice perturbation theory.
A recently developed extension of the Nambu--Jona-Lasinio model includes all the explicit chiral symmetry breaking interactions which contribute
at the same order in the large 1/Nc counting as the UA(1) ’t Hooft flavor determinant [1]. In addition to the usual 4, 6, 8 fermion vertices this
generalization includes the relevant interaction terms proportional to the current quark masses. It...
A Large Ion Collider Experiment (ALICE) was designed for the study of the strongly interacting medium created in heavy-ion collisions at LHC energies, the Quark-Gluon Plasma. Heavy quarks (charm and beauty) are very powerful probes to study this state of matter, since they are produced in the early stages of heavy-ion collisions and they traverse the QCD medium interacting with its...
We study here the interaction of DDbar* in the isospin I=1 channel in light of recent theoretical advances that allow us to combine elements of the local hidden gauge approach with heavy quark spin symmetry. We find that the exchange of light qqbar is Okubo-Zweig-Iizuka (OZI) suppressed and thus we concentrate on the exchange of heavy vectors and of two pion exchange. The latter is found to be...
We analyse the second-class current decays $\tau^{-}\to\pi^{-}\eta^{(\prime)}\nu_{\tau}$
in the framework of Chiral Perturbation Theory with Resonances.
Taking into account $\pi^{0}$-$\eta$-$\eta^{\prime}$ mixing,
the $\pi^{-}\eta^{(\prime)}$ vector form factor is extracted, in a model-independent way,
using existing data on the $\pi^{-}\pi^{0}$ one.
For the participant scalar form factor,
we...
Introduction
Chiral model with $\mbox{SU}(4)\times\mbox{U}(1)$ HLS
Relations obtained from the emergent symmetry
Numerical analysis
Summary
Within a relativistic dispersion approach based on the constituent-quark model, we extract the strong couplings of three mesons among which there is, at least, one charmonium from the residues of resonance poles in adequate transition form factors for timelike momentum transfer. Confrontation of our results with corresponding earlier ones by QCD sum rules reveals significant disagreement...
We use the local hidden gauge approach in order to study the BBbar and BBbar* interactions for isospin I=1. We show that both interactions via one light meson exchange are not allowed by the Okubo-Zweig-Iizuka rule and, for that reason, we calculate the contributions due to the exchange of two pions, interacting and noninteracting among themselves, and also due to the heavy vector mesons....
We study the physics of the strongly-correlated gluon
plasma with color-center vortices in the lattice SU(2)
simulations.
We observe in the deconfinement phase
how the equation of state, gluon propagators and
transport correlators depend on degrees of freedom of
lattice center vortices in the temporal and spatial
directions.
It is found that the magnetic sector of gluons
is more...
A new approach to study the mass spectrum of double heavy baryons containing strange and
charmed quarks is proposed. It is based on the separation of variables in the Schrödinger equation in the prolate spheroidal coordinates. Two non-relativistic potential models are considered.
In the first model, the interaction potential of the quarks is the sum of the Coulomb and non-spherically...
QCD-like theories provide testing grounds for truncations of functional equations at non-zero density, since comparisons with lattice results are possible due to the absence of the sign problem. As a first step towards such a comparison, we determine for various theories the chiral and confinement/deconfinement transitions from the quark propagator Dyson-Schwinger equation at zero chemical...
We investigate the magnetohydrodynamics in the presence of an external magnetic field following the power-law decay in proper time and having spatial inhomogeneity characterized by a Gaussian distribution in one of transverse coordinates under the Bjorken expansion. The leading-order solution is obtained in the weak-field approximation, where both energy density and fluid velocity are...
We make simulations of the zero-momentum $SU(2)$ Landau gauge gluon correlator both for periodic and zero-field boundary conditions at varying $\beta$ and $L_t * L_s^3$ lattice sizes.
I review the motivation and evidence for the center vortex confinement mechanism, including the relevance of multiple-winding Wilson loops to the confinement problem, and the recent work of Trewartha, Kamleh, and Leinweber connecting center vortices with instantons and chiral symmetry breaking.
We review lattice calculations of the elementary Greens functions of QCD with a special emphasis on the Landau gauge. These lattice results have been of interest to continuum approaches to QCD over the past 20 years. They are used as reference for Dyson-Schwinger- and functional renormalization group equation calculations as well as for hadronic bound state equations. The lattice provides...
While the crucial role of gauge topology was recognized from 1970’s,
confinement was associated with monopoles and chiral symmetry breaking with instantons.
Recognizing presence of non-zero holonomy, van Baal and others discovered
splitting of the instantons into their constituents — the instanton-dyons.
Several groups now work out properties of their ensembles, which generate
both the...
Chiral anomaly induces a variety of novel macroscopic quantum phenomena in systems possessing charged chiral fermions, including the Chiral Magnetic Effect (CME). I will review the manifestations of CME in nuclear and condensed matter physics, and present recent results on the link between CME and evolution of magnetic helicity.
Following Plato’s definition of Knowledge as Justified True Belief, Aristotle understood Reality, and our description of Reality, as the emergence of actual-observable events (ενεργεία) from potentialities (δυναμει). This model is still the basis of relating models with observations, as illustrated by the following examples: 1) selecting admissible solutions from differential and difference...
We will review the frequentist methods used in High Energy Physics for deriving limits, establishing a discovery and making a measurement in the presence of Nuisance Parameters. In particular asymptotic methods and the Look Elsewhere Effect will be reviewed.
I will review some recent progress in studying the spectra of mesons using first-principles lattice QCD calculations. In particular, I will highlight some new results on resonances, near-threshold states and related scattering phenomena – this is an area which is very interesting experimentally and theoretically and where we have made significant advances in the last few years. An...
The X, Y and Z resonances observed by BaBar, Belle, BESIII, CDF, CLEO-c, CMS, D0 and LHCb Collaborations in the last years provide a challenge to our understanding of QCD. Among them the X(3872), first observed in 2003 by Belle, is the most famous one and the X(5568), observed this year by D0, would be (if confirmed) the most recently acquisition to the list of undoubtedly exotic mesons, since...
The hadron spectrum above the open charm threshold continues to surprise and challenges our understanding of confined systems of strongly interacting particles. While for the established mesons of the X,Y and Z families we have entered the era of precision measurements, new exotic resonances are still being discovered in the meson sector and lately in the baryon sector as well. This talk will...
I will discuss new results and open challenges in open heavy flavor and
quarkonium production in $p+p$ and $p+$Pb collisions at the LHC.
I will discuss (QCD)-techniques and calculations for dark matter production at the LHC, but also briefly review the physics case and the theoretical status of dark matter models.
I review current anomalies seen in the quark flavor sector at LHCb and the B factories. I then discuss a simple and minimal model, which can resolve these anomalies in an elegant way.
When an excess appears in LHC data, we should be comparing the data with entire classes of models, to get an immediate sense of which ones could conceivably be relevant. Often, the new physics is likely to be a relatively narrow s-channel resonance. In this case, a simplified model of the resonance can translate an estimated signal cross section into model-independent bounds on the product of...
The most accurate method to combine measurement is to build a combined likelihood function and use it to perform the desired inference. This is not always possible for various possible reasons, hence approximate methods are often convenient. Among those, the best linear unbiased estimator (BLUE) is the most popular, allowing to take into account individual uncertainties and their correlations....
We compute leading-power fragmentation corrections to $J/\psi$
photoproduction at DESY HERA, making use of the nonrelativistic QCD
factorization approach. Our calculations include parton production cross
sections through order $\alpha_s^3$, fragmentation functions though
order $\alpha_s^2$, and leading logarithms of the transverse momentum
divided by the charm-quark mass to all orders in...
We summarize results on the internal structure and properties of the pion and kaon as an illustration of how insights into hadron physics can be obtained from calculations based on the Dyson-Schwinger equations of QCD. The light pseudoscalar mesons are the best possible case for such considerations as the approach is very well-constrained by symmetries and there is direct connection to...
Motivated by the striking modifications of jets observed both at RHIC and the LHC, significant progress towards the understanding of jet dynamics within QGP has occurred over the last few years. In this talk, I review the recent theoretical developments in the study of medium-induced jet evolution and energy loss within a perturbative framework. The main mechanisms of energy loss and...
Permanent Electric Dipole Moments (EDM) of hadrons and leptons provide a unique probe for physics beyond the Standard Model (SM). As EDMs violate P and T symmetries, they also provide information about the matter-antimatter asymmetry in the universe. Although the SM prediction for EDMs is beyond the reach of current experiments, the experiments set stringent limits on many beyond SM models. In...
The properties of matter at finite baryon densities plays an
important role for the astrophysics of compact stars as well as for heavy
ion collisions or the description of nuclear matter. Because of the
sign problem of the quark determinant, lattice QCD cannot be
simulated by standard Monte Carlo at finite baryon densities.
I describe an alternative attempt to treat
dense QCD with an...
ALICE (A Large Ion Collider Experiment) is studying the physics of strongly interacting matter, and in particular the properties of the Quark-Gluon Plasma (QGP), using proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN LHC (Large Hadron Collider). The ALICE Collaboration is preparing a major upgrade of the experimental apparatus, planned for installation in the second...
We study higher order relativistic corrections to the electromagnetic production cross-section of a heavy quarkonium and a hard photon in the factorization framework of non-relativistic QCD (NRQCD). We obtain new matching coefficients and discuss the importance of contributions from color octet operators, that were not considered in the previous studies of this process.
ALICE is the only LHC experiment specifically devoted to the study of ultra-relativistic heavy ion collisions. Its main goal is to identify and study a new state of matter, le Quark Gluon Plasma (QGP), where quarks and gluons are deconfined, which might have existed during the first instants of the Universe. One of the most powerful signatures for QGP study is the suppression, within this hot...
I will provide an overview of various leading contributions to neutron electric dipole moment (EDm) from both the standard model and beyond the standard model and then summarize the status of lattice QCD calculations of the matrix elements of two of the leading novel CP violating interactions -- the quark EDM and the quark chromo EDM.
Three-flavor chiral perturbation theory with $t,b,c$ quarks decoupled tests the infrared limit of three-flavor QCD. The standard theory $\chi$PT$_3$ (before being unitarized) assumes that there is no infrared fixed point $\alpha_{\mathrm{IR}}$. If $\alpha_{\mathrm{IR}}$ exists, we get chiral-scale perturbation theory $\chi$PT$_\sigma$ about a scale-invariant theory where the quark condensate...
Often physicists need to calculate the confidence interval for the ratio of two measurements and many times just use the so-called “error propagation” of the corresponding uncertainties, without being aware of the approximations involved and the limitations of this approach. We will explore these limitations, as well as some alternative and more accurate methods. “Exact” methods for the case...
We discuss the evolution of an energetic jet which propagates through a dense quark-gluon plasma
and radiates gluons due to its interactions with the medium. Within perturbative QCD, this
evolution can be described as a stochastic branching process, that we have managed to solve exactly.
We present exact, analytic, results for the gluon spectrum (the average gluon distribution)
and for...
The LLR method was recently proposed for numerical computations of continuous density of states. The density of states approach is particularly useful when dealing with meta-stabilities and for computing free-energies. In this talk I will review the method and discuss compact U(1) Lattice Gauge Theory, for which our algorithm has proved to be highly efficient and provided results that...
References:
[1] J/Psi -pair production at large momenta: Indications for double parton scatterings and large alpha_s^5 contributions. By J.P. Lansberg, H.S. Shao. arXiv:1410.8822 [hep-ph]. Phys.Lett. B751 (2015) 479.
[2] Production of J/psi+eta(c) vs. J/psi+J/psi at the LHC: Impact of Real alpha_s^5 corrections. By J.P. Lansberg, H.-S. Shao. [arXiv:1308.0474 [hep-ph]]. Phys.Rev.Lett....
The muon g-2/EDM proposed experiment at J-PARC is a promising and innovative attempt at the field of Precision Physics. The sensitivity goal of 0.1ppm will test the limits of our current understanding, and may probe for BSM observations.
Our project seeks out to investigate the computational techniques required by the experimental process.
The GEANT4 framework was used to simulate the...
Permanent electric dipole moments (EDMs) are sensitive probes of CP violation beyond the Standard Model. EDM experiments typically involve complicated systems such as hadrons, nuclei, and atoms. I will discuss an effective field theory framework in which EDM measurements can be interpreted in terms of more fundamental concepts. As an example, I illustrate how EDM measurements set strong...
In this work, we pint out that there exists an approximate degeneracy among heavy-light systems with the same $L$.
This is supported by an experimental fact which can be seen from the observed data. This approximate symmetry explains why the GI model obtains results similar to those of the heavy-light systems which are fitted well with experimental data. This is because the GI model has this...
The precise SIDDHARTA value of the energy shift and width of kaonic hydrogen has awaken a renewed interest for the meson-baryon interaction in the $S=-1$ sector. Our study has been carried out based on a chiral SU(3) Lagrangian up to next-to-leading order (NLO) and implementing unitarization in coupled channels, since the presence of $\Lambda(1405)$ resonance makes not applicable a...
The research programme of the ALICE experiment at the LHC focuses on studies of the Quark-Gluon Plasma, a state of matter where quarks and gluons are deconfined. The measurement of jets originating from the fragmentation of hard-scattered partons in the early phases of a nuclear collision allows one to study parton energy loss in the hot and dense medium. The dependence of the energy loss on...
Based on
Estimating the significance of a signal in a multi-dimensional search
Ofer Vitells, Eilam Gross (Weizmann Inst.). May 2011. 5 pp.
Published in Astropart.Phys. 35 (2011) 230-234
Studies of QCD-like theories without a fermion sign problem at finite density by now have a rather long history already. I will report recent results from two-color QCD, with two instead of the usual three colors, and $G_2$-QCD, with gauge group $G_2$ instead of $SU(3)$. Both have bosonic diquark baryons. The physics of those is believed to be fairly well understood and qualitatively resembles...
We will give an overview about the current state of the calculation of di-boson
production. For precision measurements at the LHC both NNLO QCD and NLO EW
corrections are important. The Di-boson production processes give access to
triple gauge couplings and possible modifications in the form of anomalous
couplings (AC). We will present a study on WZ production with AC at approximate
NNLO...
In high energy physics experiments a CsI photocathode coupled to a gaseous detector is used in most of the RICH detectors to identify charged hadrons. These RICH detectors have shown to be efficient and stable over long periods of time. A review of the important RICH detectors used around the world, and the technology behind them, will be shown.
Long-range multiplicity correlations in intervals separated in pseudorapidity and azimuth are studied in the framework of string fusion approach.
We applied a Monte Carlo model [1,2], in which the string configurations in the transverse plane and rapidity are simulating event-by-event.
We assumed that the azimuthal anisotropy of particle production is caused by parton energy loss travelling...
We determine the $1/m$ and $1/m^2$ spin-independent heavy quarkonium potentials in the unequal mass case with $\mathcal O (\alpha^3)$ and $\mathcal O (\alpha^2)$ accuracy, respectively. Furthermore, we discuss in detail different methods to obtain the potential and we provide the explicit field redefinition that relates them, thus clarifying the relation between different previous partial...
Recently, the GWU lattice group has evaluated high-precision phase-shift data for $\pi\pi$ scattering in the $I=1$, $J=1$ channel. Unitary Chiral Perturbation Theory describes these data well around the resonance region and for different pion masses. Moreover, it allows to extrapolate to the physical point and estimate the effect of the missing $K\bar{K}$ channel in the two-flavor lattice...
A method is presented for the reduction of large sets of related uncertainty sources into strongly reduced representations which retain a suitable level of correlation information for use in many cases. The method provides a self-consistent means of determining whether a given analysis is sensitive to the loss of correlation information arising from the reduction procedure. The method is...
We extract an effective Polyakov line action from an underlying SU(3) lattice gauge theory with dynamical fermions via the relative weights method. The center-symmetry breaking terms in the effective theory are fit to a form suggested by the hopping-parameter expansion, and the effective action is solved at finite chemical potential by a mean field approach. We show results for a small sample...
A collaborative effort to determine the $\Lambda$-parameter in 3-flavour
QCD by the ALPHA collaboration has just been finalized. This requires the precise
connection of vastly different energy scales, which is achieved using suitable
running couplings in finite volume renormalization schemes and recursive step-scaling methods.
In this talk I focus on the scale evolution from an intermediate...
The main goal of the CBM experiment at FAIR is to study the behaviour of nuclear matter at very high baryonic density in which the transition to a deconfined and chirally restored phase is expected to happen. The promissing signatures of this new state are the enhanced production of multi-strange particles, production of hypernuclei and dibaryons. Theoretical models predict that single and...
We use holography to analyze the evolution of an ensemble of jets, with an initial probability distribution for their energy and opening angle as in proton-proton (pp) collisions, as they propagate through an expanding cooling droplet of strongly coupled plasma as in heavy ion collisions. We identify two competing effects: (i) each individual jet widens as it propagates; (ii) the opening angle...
Huge magnetic fields (MF) up to eB value of the order of the QCD Lambda square are created
for a short time in peripheral heavy ion collisions at RHIC and LHC.The field about four
orders of magnitude less is anticipated to operate in magnetars.This brought about an
extraordinarly large interest to the behavior of quark systems (mesons and baryons) in strong MF.In a series of papers we...
Our formalism is based on the Covariant Spectator Theory (CST), a framework based on field theory originally developed to study systems of few nucleons. The distinctive feature of this approach is that it approximates the full Bethe-Salpeter-equation by taking into account, effectively, the contributions of both ladder and crossed ladder diagrams in the kernel.
Another notable feature of...
In this talk we present the ALPHA-collaboration computation of the three-flavour QCD $\Lambda$-parameter. Starting from the value of $\Lambda$ in units of an intermediate energy scale $\mu=1/L_0 \sim 4\, {\rm GeV}$ (cf. talk by S. Sint), we first discuss the connection of this scale and a given hadronic scale, $1/L_{\rm had}$, of a few hundred MeV. The latter is obtained very precisely by...
I begin with an introduction to deep learning methods and the kinds of problems in particle physics to which the methods could be usefully applied, such as searching data for evidence of new physics. Then I discuss the Bayesian connection. I conclude with a perspective on what data analysis might look like in the not too distant future.
The Large Hadron electron Collider (LHeC) is a proposed facility which will exploit the new world of energy and intensity oered by the LHC through collisions with a new 60 GeV electron beam. Designed for synchronous operation with the other LHC experiments, the LHeC will be a high luminosity ep and eA collider with a wide ranging physics program on high precision deep inelastic scattering and...
We present a new Higgsless model of superconductivity, inspired from anyon superconductivity but P- and T-invariant and generalizable to any dimension. While the original anyon superconductivity mechanism was based on incompressible quantum Hall fluids as average field states, our mechanism involves topological insulators as average field states. In D space dimensions it involves a (D-1)-form...
We calculate the next-to-next-to-leading correction to the expectation value of the Polyakov loop or equivalently to the free energy of a static charge. This correction is of order $g^5$. We show that up to this order the free energy of the static charge is proportional to the quadratic Casimir operator of the corresponding representation. We also compare our perturbative result with the most...
Recent advances in experiments of the symmetry energy of nuclear matter and in neutron star observations yield important new insights on the equation of state of neutron matter at nuclear densities. In this regime the equation of state of neutron matter plays a critical role in determining the mass-radius relationship for neutron stars. We show how microscopic calculations of neutron matter,...
A myriad of new techniques and technologies made it possible to inaugurate the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory as the world's first high-energy polarized proton collider in December 2001. RHIC delivers polarized proton-proton collisions at center-of-mass energies of up to 500 GeV. This unique environment provides opportunities to study the polarized...
We extend the covariant variational approach for Yang-Mills theory
in Landau gauge to non-zero temperatures. The renormalization of the system
is revisited and it is shown how the zero-temperature counter terms can be
used to render the system finite at any temperature. Numerical solutions
for the thermal propagators are presented and compared to high-precision
lattice data. To...
This talk will be based on the e-print "X(3872) production and absorption in a hot hadron gas", arXiv:1604.07716.
Report at the Session: Future Perspectives, Upgrades, Instrumentation
Vertex detector for open charm measurements with NA61/SHINE at SPS at CERN
G.A.Feofilov $^1$$^†$ (for NA61/SHINE Collaboration)
(1) Saint-Petersburg State University
$^†$ E-mail: feofilov@hiex.phys.spbu.ru
Search for the critical point of strongly interacting matter and studies of the onset of deconfinement are...
Statistical classification models are commonly used to separate a signal from a background. In this talk we face the problem of isolating the signal of the double Higgs production using the decay channel in which each boson decays into a pair of b-quarks. Typically in this context non parametric methods are used, such as Random Forest or different types of Boosting. We remain in the same non...
This report is devoted to the study of the QCD phase diagram with nonzero chiral chemical
potential within lattice simulation. In particular, it is studied the question how nonzero
chiral chemical potential influences the transitions: confinement/deconfinement and
breaking/restoration of chiral symmetry. The results of the calculation can be
explained by the phenomenon which we called...
Since the discovery of the $X(3872)$ in 2003 [1] it became evident that the naive
quark model would not be enough to describe all the baryon spectrum. This state
has properties that can not be explained in such a quark model, as its decay into
$J/\Psi \pi \pi$ through a $\rho$ meson, which is an isospin violating decay. However
this property can be easily explained in a picture in which...
The crust of a neutron star has a profound influence on various observed astrophysical phenomena such as pulsar sudden spin-ups, quasi-periodic oscillations in the giant flares from soft gamma-ray repeaters, X-ray bursts and superbursts, or the cooling of transiently accreting neutron stars. We have determined the internal constitution and the equation of state of neutron-star crusts in the...
I will discuss the phenomenon of quark liberation on domain walls in gauge theories which are confining in the bulk. Specifically I will discuss confinement-preserving compactifications of such theories. These are confining due to the magnetic bion mechanism. I will show that liberation on domain walls becomes natural in such theories. I will also discuss the spin-1/2 or “spinon” confinement...
The COMPASS experiment at CERN took the first ever polarized Drell-Yan data in 2015. The muon pairs originating from pion induced collisions provide a way of accessing the transverse
momentum dependent parton distribution functions of the nucleon. The study of the azimuthal spin asymmetries in Drell-Yan complements a wealth of results already obtained from transversely polarized semi-inclusive...
I review recent developments in QCD thermodynamics and collective excitations from the hard-thermal-loop effective theory. I begin by motivating the discussion with open questions from heavy-ion collisions. I then discuss a finite-temperature and density calculation of QCD thermodynamics at NNLO from the hard-thermal-loop perturbation theory. Finally, I discuss a recent exploration of...
The Micro Vertex Detector (MVD) will consist of four planar detector stations located at 5cm to 20cm downstream the target.
Its design is driven by the challenge to identify the decay vertices of particles carrying open-charm, which calls for a high spatial resolution ($\sim 5\mu m$) and a very light material budget of $0.3\%\ (0.5\%)\ X_0$ for the first (following) stations.
To match these...
Using large data samples of di-muon events, CMS has performed detailed measurements and searches for new states in the field of exotic quarkonia. We report on measurements of the charmonium X(3872), and search for its counterpart in the bottomonium sector. The investigation of the B+ to J/ψ φ K+ decay reveals two structures in the J/ψ φ mass spectrum. For the one closest to the kinematical...
Studies of the QCD phase diagram at finite temperature and quark chemical potential are currently one of the most discussed topics in theoretical physics and are of great importance to better our understanding of heavy-ion collision experiments. However, there is considerable uncertainty about the detailed structure of the QCD phase diagram at high baryon densities. Models provide some insight...
Regular operation of the VEPP-2000 electron-positron collider started at the end of 2010 and about 60 pb$^{−1}$ were collected so far by the CMD-3 detector in the whole available c.m. energy range from 0.32 GeV to 2.0 GeV. These measurements allow improvements in the precision of the predicted value of the muon anomalous magnetic moment. We report here current results of analysis of the...
The problem of correcting data for detector effects (unfolding) is
disussed, with emphasis on practical difficulties showing up
in particle physics. A selection of unfolding methods
commonly used in particle physics is presented, such as
iterative algorithms (D'Agostini), methods based on matrix
decomposition (SVD unfolding) and fits with Tikhonov regularisation
(TUnfold). The...
Modern and future heavy-ion experiments are focused on measurements of very rare particles at interaction rates up to 10 MHz with data flow of up to 1 TB/s, that cannot be fully stored on currently available storage devices. The data flow should be reduced by selecting collisions with potentially interesting physics. Therefore, full reconstruction of the collision topology including...
We consider a quantum annealing simulation optimized for lattice QCD, reflecting the nonlinear network topology of the Kuramoto model where all the oscillators are considered to have distinct intrinsic natural frequency and a coupling scheme in which the optimum weight of a link to neighboring sites depends on the number of shortest paths crossing it. The onset of synchronization relies on...
The heavy-quark spin symmetry (HQSS) partners of the X(3872) molecule are investigated based on a chiral effective field theory (EFT) approach involving contact and one-pion exchange interactions. The integral equations of the Lippmann-Schwinger type are solved for a coupled-channel problem involving the $D\bar D, D\bar{D}^*$, and $D^*\bar{D}^*$ interactions to yield the scattering...
We investigate Landau gauge $SU(3)$ Yang-Mills theory in a
systematic vertex expansion scheme for the effective action with
the functional renormalisation group.
Particular focus is put on the dynamical creation of the gluon mass
gap at non-perturbative momenta and the consistent treatment of
quadratic divergences. The non-perturbative ghost and transverse
gluon propagators as well as...
The computation of single particle spectral functions and transport coefficients with functional continuum methods is discussed. Results are presented for quark and meson, and glueball spectral functions, as well as the temperature-dependent shear viscosity over entropy ratio.
This work is based on
1) Low energy chiral two pion exchange potential with statistical uncertainties
By R. Navarro Pérez, J.E. Amaro, E. Ruiz Arriola.
arXiv:1411.1212 [nucl-th].
10.1103/PhysRevC.91.054002.
Phys.Rev. C91 (2015) no.5, 054002.
2) Partial Wave Analysis of Chiral NN Interactions
By R. Navarro Perez, J.E. Amaro, E. Ruiz Arriola.
arXiv:1310.8167...
The main goal of the High Acceptance Di-Electron experiment (HADES) [1] at GSI is the study of hadronic matter in the $1-3.5$ GeV/nucleon incident energy range. The obtained dilepton spectra measured in nucleon-nucleon, nucleon-nucleus and heavy-ion reactions at various beam energies demonstrate important contributions from baryon resonances decays ($R\rightarrow Ne^+e^-$). The...
One of the most challenging questions in contemporary physics is why and how quarks are confined into hadrons. The electromagnetic structure of hadrons, parameterised in terms of electromagnetic form factors, EMFF's, can provide a key.
The focus of this talk is baryon EMFF's. EMFF's have been a powerful tool in understanding the structure of nucleons for more than 60 years but the new...
We show that effective field theory techniques can be applied
in the high temperature T plasmas to
improve the accuracy of the physics of the hard scales ( or scales of order T).
At leading order in the
coupling constant the hard scales of the plasma can be viewed as
on-shell classical particles. Based on this observation, and without any
reference
to the state of the system, we...
In ATLAS, several unfolding methods are used to correct experimental measurements for detector effects, like acceptance and resolution. These methods use as input the raw experimental distributions, as well as Monte Carlo simulation for the description of the detector effects. The systematic uncertainties associated to the various unfolding methods are evaluated. The statistical and systematic...
A massive expansion, based on massive free-particle propagators,
can be set up from first principles[1-3] and shown to be
a powerful variational tool disguised to look like a perturbative approximation[3].
By its optimization, the method provides an analytical tool for exploring the
propagators of QCD deep in the infrared of Minkowski space[3] and from first principles,
without having...
The hidden charm pentaquark state $P_c(4450)$, observed recently by the LHCb collaboration in the $\Lambda_b \rightarrow J/\psi K^- p$ decay, may be of molecular nature, as advocated by some unitary approaches that also predict pentaquark partners in the strangeness S=-1 sector. In this work we argue that a hidden-charm strange pentaquark could also be seen in the decay of the $\Lambda_b$,...
High-energy peripheral reactions provide an excellent opportunity to study the excitation spectrum of hadrons. The COMPASS experiment at CERN has measured the diffractive scattering of pions to the 3-pion final state with unprecedented statistical precision. Partial wave analysis techniques have been employed to obtain an expansion of the reaction cross section in terms of partial waves with...
I advocate a proposal that two of the largest open questions in cosmology, the origin of the matter/antimatter asymmetry and the nature of the dark matter (DM), may have their origin within a single theoretical framework. Furthermore, both effects may originate at the same cosmological epoch from one and the same QCD physics when the $\theta$ parameter was not zero. This source of the strong...
The gauge field theory approach, which allows a natural way to introduce collective degrees of freedom and nonlinear topological structures based on fundamental principles of gauge symmetry is considered. This approach use description of the local geometry of proteins based on the formalism of discrete coordinates of Freney. Under this formalism, proteins are considered as one-dimensional...
By breaking the initial SU(N) symmetry, we derive the Lagrangian[1] governing the dynamics of the massive scalar particles, which can be treated as the octet of the pseudoscalar mesons. The contribution of both the quark-gluon interaction and self-interaction gluon field into the masses of the octet particles is considered. Provided that the hadronization of the confinement matter into...
Centrality, as a geometrical property of the collision, is crucial for the physical interpretation of nucleus-nucleus and proton-nucleus experimental data. However, it cannot be directly accessed in event-by-event data analysis. Contemporary methods of the centrality estimation in A-A and p-A collisions usually rely on a single detector (either on the signal in zero-degree calorimeters or on...
In the ever increasing pile-up of the Large Hadron Collider environment the trigger systems of the experiments have to be exceedingly sophisticated and fast at the same time in order to increase the rate of relevant physics processes with respect to background processes.
The Fast TracKer (FTK) is a track finding implementation at hardware level that is designed to deliver full-scan tracks...
Exotic Mesons Production, All charm tetra quark, Double Parton Scattering, Color Evaporation Model.
We investigate the phase diagram of QCD with heavy quarks at finite temperature and chemical potential in the context of background field methods. In particular, we use a massive extension of the Landau-DeWitt gauge which is motivated by previous studies of the deconfinement phase transition in pure Yang-Mills theories. We show that a simple one-loop calculation is able to capture the richness...
I review the recent finite temperature lattice results that push
the simulations to the limits. The covered topics include the
hadronic degrees of freedom near Tc, very high temperatures,
finite density, and attempts to extract real time physics from
Euclidean correlators.
Recent theoretical developments in the description of collisions involving jets will be discussed, as well as the insights they shed on the nature of jets and the experimental ramifications for pp and heavy ion collisions.
I will discuss the properties of neutron matter from very low to very high density.
At low densities dilute neutron matter is very similar to cold atoms with an energy nearly a constant times the Fermi gas and a very large pairing gap. At higher densities the superfluid pairing is dramatically reduced. Above saturation densities the equation of states controls the mass radius relation of...
There are many interesting problems in heavy-ion collisions and in cosmology that involve the interaction of a heavy particle with a medium. An example is the dissociation of heavy quarkonium seen in heavy-ion collisions. This was believed to be due to the screening of chromoelectric fields that prevents the heavy quarks from binding, however in the last years several perturbative and lattice...
The energy loss and degree of thermalization of charm and beauty quarks in a quark-gluon plasma is one of the key observables to probe this medium. Spectra and azimuthal anisotropies of open charm hadrons are reported on and first results on open beauty are becoming available. Of crucial relevance are also the total charm and beauty production cross sections. Quarkonia habe long been...
One of the main surprises brought by the heavy ion program at the LHC is the observation of long-range correlations in collisions involving relatively small systems, like proton-proton or proton-lead. Similar phenomena were previously observed in collisions between two heavy nuclei, like Au+Au (at RHIC) and Pb+Pb (at the LHC) and in that context they were associated with collective phenomena,...
Based on the new fit of hadron yield ratios within the multicomponent hadron resonance gas model we have found several remarkable irregularities at chemical freeze-out. In particular, 121 hadron multiplicity ratios measured in the nucleus-nucleus collisions at AGS, SPS and RHIC energies were successfully described within the new formulation of HRGM with $\chi^2/dof \simeq 63.978/65 \simeq...
A Large Ion Collider Experiment (ALICE) was designed for the study of the strongly interacting medium created in heavy-ion collisions at LHC energies, the Quark-Gluon Plasma. Heavy quarks (charm and beauty) are very powerful probes to study this state of matter, since they are produced in the early stages of heavy-ion collisions and they traverse the QCD medium interacting with its...
We present a first-principles study of anomaly induced transport phenomena by performing real- time lattice simulations with dynamical fermions coupled simultaneously to non-Abelian SU(Nc) and Abelian U(1) gauge fields. We investigate the behavior of vector and axial currents
during a sphaleron transition in the presence of an external magnetic field, and demonstrate how the interplay of the...
We present novel method for the organisation of events. The method is based on comparing event-by-event histograms of a chosen quantity $Q$ that is measured for each particle in every event. The events are organised in such a way that those with similar shape of the $Q$-histograms end-up placed close to each other.
We apply the method on histograms of azimuthal angle of the produced hadrons...
We have derived all WIMP-nucleon interactions in chiral EFT to third order in the chiral expansion, including all one- and two-body currents. Because the relevant momentum transfers involved in WIMP scattering off nuclei are of the order of the pion mass, this is a prime regime for chiral EFT.
Combined with large-scale nuclear structure calculations, we have studied spin-dependent...
Strong magnetic backgrounds are known to modify QCD properties
at a non-perturbative level. We will discuss recent lattice results,
obtained for N_f = 2+1 QCD with physical quark masses, concerning
in particular the modifications and the anisotropies induced at the
level of the static quark-antiquark potential and of other confining
properties of strong interactions.
In this talk I will review recent efforts in constraining the photon and dilepton rates on the theory side. This is achieved by extending perturbative calculations to next-to-leading order in the coupling $g$ both for photons and for dileptons in most kinematical regions. A polynomial interpolation for the corresponding spectral function, which vanishes at zero frequency and matches to these...
I will review activities of the Joint Physics Analysis Center
We present the results of a low-temperature scan of the phase diagram of
dense two-color QCD with N_f = 2 quarks. The study is conducted using lattice simulation
with rooted staggered quarks. At small chemical potential we observe the hadronic phase,
where the theory is in a confining state, chiral symmetry is broken, the baryon density is
zero and there is no diquark condensate. At the...
In the last decade many states in the spectrum of charmonium and bottomonium lying above the open-flavour threshold have been observed experimentally. Most of these states reside in the vicinity of strong thresholds and cannot be described by simple quark models. Description and understanding of such exotic states is a challenge for phenomenology of strong interactions which requires building...
Many challenges, such as determining significance, exist in identifying new structures in hadron spectra. This talk will summarize first-hand experience on significance determination including look-elsewhere-effect, background determination, as well
as signal extraction in hadron spectra.
Hadron spectroscopy is one of the most important physics goals of BESIII. BESIII brings great opportunities to study the XYZ states of charmonium by directly producing the Y states up to 4.6 GeV. We focus on the investigation of XYZ states and the discovery of new charged charmonium-like structures. Two isospin triplets Z(3900) and Z(4020) have been discovered, decaying into J/psi pi and hc...
In this talk we will review recent progress in hadron structure using lattice
QCD simulations, with main focus in the evaluation of nucleon matrix elements.
We will highlight developments that may guide New Physics searches, such as the
scalar/tensor charges, and neutron electric dipole moment. We will also give
updates on a new direct approach to compute quark parton distributions...
One of the most important result obtained at RHIC experiment is the measurement of the elliptic flow of final
particles. The value of this flow can be explained within hydrodynamic
approach, if it is assumed that QGP is nearly perfect fluid. Our paper is devoted to calculation of
shear viscosity of QGP at different temperatures within lattice simulation of QCD. The results of...
We discuss the confinement mechanism based on nonAbelian variety of dual superconductivity. Important hints come from physics of strongly-coupled infrared-fixed-point theories in N=2 supersymmetric QCD, which turn into confining vacua under a small relevant perturbation. The quest for the semiclassical origin of these nonAbelian monopoles, ubiquitous as the infrared degrees of freedom of...
We study the effect of magnetic field on the photon emission
from the quark-gluon plasma (QGP) in AA collisions at RHIC and LHC energies.
We develop a formalism for photon radiation from the QGP
which accounts for interplay of the synchrotron mechanism and
the photon emission due to multiple scattering.
We show that multiple scattering suppresses strongly the
synchrotron contribution....
The goal of the COMPASS experiment at CERN is to study the structure and dynamics of hadrons. The two-stage spectrometer used by the experiment has good acceptance and covers a wide kinematic range for charged as well as neutral particles allowing to access a wide range of reactions. Light mesons are studied with negative (mostly $\pi^-$) and positive ($p$, $\pi^+$) hadron beams with a...
The combination of experimental results requires a careful statistical treatment. We review the methods and tools used in ATLAS for the statistical combination of measurements and of limits on new physics. We highlight the methods used in the recent combination of ATLAS and CMS measurements of the Higgs boson production/decay rates and the constraints on the Higgs coupling parameters.
We derive three exact sum rules for the spectral function of the electromagnetic current channel at finite temperature, by using operator product expansion and hydrodynamics, focusing on zero spatial momentum case. We also discuss the possibility to use these sum rules to constrain and improve the functional form of the spectral function assumed in the lattice QCD analysis, and to evaluate the...
In the last decade new, unexpected, quarkonium states close and above open flavor thresholds have been discovered. Some of these states are candidates for quarkonium hybrids, i.e states containg a gluonic excitation. Quarkonium hybrids are characterized by a set of well separated scales, in particular, the heavy quark and gluon dynamics have very different dynamical time scales, that be...
Neutrinoless double-beta decay is a lepton-number violating process that will establish that neutrinos are its own antiparticle. In the next few years, ton-scale experiments will aim for the detection of this rare decay. Naturally, the nuclear decay rate depends on the nuclear matrix element of the transition (NME). The NMEs are necessary to constrain the neutrino mass from limits on the decay...
Electromagnetic probes are penetrating and are thus particularly useful to study the initial state and the earliest phases of hadron and heavy-ion collisions. However, because of the low cross section the measurements suffer from a small signal to background ratio and are therefore extremely challenging.
Prompt photon and Drell-Yan production are sensitive probes of the initial parton...
Neutrinoless double beta decay searches play a major role in determining properties of neutrinos as well as nuclei. The double-beta decay with neutrinos is one of the rarest process in the world. It has been observed in only a few nuclei so far. The even rarer process of neutrinoless double-beta decay will have a major impact on the current Standard
model. It would show that neutrinos are...
The nucleon excitation scheme has been under intensive investigation with meson photoproduction experiments during the last few years world wide. Currently, a lot of new experimental results are coming out from the CLAS experiment at Jlab, the Crystal Barrel experiment at the ELSA accelerator in Bonn and the Crystal Ball experiment at the MAMI accelerator in Mainz. These experiments focus on...
We study a Random Matrix Model for QCD at finite density via Complex Langevin dynamics. This model has a phase transition to a phase with non-zero baryon density. We study the convergence of the algorithm as a function of the quark mass and the chemical potential and focus on two main observables: the baryon density and the chiral condensate. As expected, for simulations close to the chiral...
In the framework of pNRQCD, we calculate the partial decay width of heavy hybrid states to heavy quarkonia, and the mixing potential between them. We discuss their phenomenological relevance concerning the identification of some XYZ states with heavy hybrids.
We present the calculation of the next-to-leading order in the heavy quark-antiquark potentials within the framework of the effective string theory. Elaborate arguments for simplifying and reducing the number of dimensionful parameters of the effective string theory are also discussed.
A new data-driven technique for modelling the QCD multijet background component for analyses which include several jets in their final state is presented and studied in detail. By combining pairs of hemispheres from other events based on a nearest neighbour distance, a new mixed dataset can be constructed which kinematically resembles the majority component of the original mixture. Therefore,...
We investigate the thermal-photon emission from strongly coupled gauge theories at finite temperature via the bottom-up models in holographic QCD in the deconfined phase. Particularly, we apply a model encoding flavor degrees of freedom in the Veneziano limit of a large number of colors $N_c$ and flavors $N_f$ but fixed $x=N_f=N_c$ (VQCD). In this model, the normalization and gauge-field...
We want to discuss the Pc(4450) pentaquark-like structure observed by the LHCb Collaboration in the J/psi proton final states. We point out that it is located exactly at the chi_{c1}-proton threshold, and coincides with the leading Landau singularity of the triangle loop Lambda(1890)-chi_{c1}-proton. We also discuss the possibility of distinguishing a genuine resonance from the kinematical singularity.
We present results for correlators and spectral functions of open and hidden charm mesons using 2+1 flavours of clover fermions on anisotropic lattices. The D mesons are found to melt close to the deconfinement crossover temperature $T_c$. Our preliminary results suggest a shift in the thermal D meson mass below $T_c$.
Initially, we discuss a family of gauge fixing conditions that detect sectors of magnetic defects in continuum YM theories. The BRST symmetry cannot be globally defined, due to sector-dependent regularity conditions on the ghosts fields. This opens a window for the space of quantum states to be different from that implied when defects are removed. Next, we review how to integrate the partial...
We report on BESIII measurements of the timelike pion form factor obtained via the initial state radiation technique, the decays of $\eta^\prime$ into the final states $\pi^+\pi^-\gamma$, $e^+e^-\gamma$ as well as the observation of the $\eta^\prime$ decay into $\omega e^+e^-$.
Nuclear collisions at high energies produce large numbers of secondaries.
Results from the ALICE collaboration show that more than 20 000 of them are produced in a Pb-Pb collision. In view of this it is natural to consider a statistical-thermal model to analyse these and concepts like temperature, energy density, pressure, net baryon density etc... are useful.
A presentation will be given...
Formation of color flux tubes (or quark-gluon strings), at very early stages of hadron- hadron collision, and the following hadronization, is the common general concept used by various event-generators of multiparticle production. The mechanisms of strings formation might be different (in soft and hard processes), however, the common feature in all model approaches is the number of strings...
Pion-exchange offers a natural explanation for Pc(4450)+ as a meson-baryon molecule, and implies a number of partner states. I discuss the properties of these partners and suggest experimental channels for their discovery. The molecular interpretation also implies that Pc(4450)+ is a mixture of isospins 1/2 and 3/2, which has characteristic signatures in production and decay. Several...
The observed matter-antimatter asymmetry of the universe is an outstanding mystery of physics that cannot be explained within the Standard Model. Many beyond the Standard Model (BSM) explanations have been proposed, and experimental data is needed to constrain the wide theory space of BSM models. Neutron-antineutron oscillations are predicted to be a signature of some BSM baryogenesis models...
At finite baryon density lattice QCD first-principle calculations can not be
performed due to the sign problem. In order to circumvent this problem, we
use the canonical approach, which provides reliable analytical continuation
from the $\mu_q^{Im.}$ region to the real chemical potential region. We briefly
present the canonical partition function method, describe our formulation, and
show...
- Introduction
- Conventional Higgs mechanism
- Higgs-Confinement: SU(2) case
- Higgs-Confinement: SU(3) case
- Conclusion and discussion
The requirement of having a consistent S-matrix can impose highly non-trivial constraints on effective field theories. In particular, we show how supersymmetry constrains the effective action of N=4 SYM in the Coulomb branch and we introduce new constraints coming from breaking conformal symmetry in the form of soft theorems. Finally, we also discuss the interplay between scale and conformal...
X(4260) and X(4360) mesons
Modifications in magnitude of fluctuations for different observables
are an excellent probe of a phase transition or its remnant.
In heavy-ion collision, fluctuations related to conserved charges
carried by light and strange quarks play an important role to identify
the QCD chiral crossover and deconfinement properties.
Recent Lattice QCD simulations have revealed that the charmed...
Strong diquark correlations inside baryons is a consequence of two emergent phenomena in Quantum Chromodynamics (QCD): dynamical chiral symmetry breaking and confinement. That is to say, any interaction capable of creating pseudo-Goldstone modes as bound-states of a light dressed-quark and -antiquark, will necessarily also generate strong colour-antitriplet correlations between any two dressed...
The recent observation by the LIGO collaboration of black hole merges using gravitation waves opens a new portal to study our universe. The sensitivity of gravitation waves measurements is likely to be extended in the coming future to allow the detection and study of neutron stars merges. Such merges are thought to be the main source for r-process nuclear synthesis and can potentially act as a...
Graphical Processing Units (GPUs) represent one of the most sophisticated and versatile parallel computing architectures available that are nowadays entering the High Energy Physics field. GooFit is an open source tool interfacing ROOT/RooFit to the CUDA platform on nVidia GPUs. Specifically it acts as an interface between the MINUIT minimisation algorithm and a parallel processor which allows...
The Green's functions of QCD encode the properties of hadrons,
with the appearance of (colour singlet) poles in n-point functions
corresponding to bound-states and resonances. There are several
techniques by which such information may be extracted, including
lattice QCD and functional methods. We discuss recent progress in
applying nPI effective action techniques to the systematic...
The number of multiquark states and the amount of details on their properties has been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of four tetraquarks, two of which had not been observed before. We present some considerations attempting a coherent description of the so called X and Z resonances. The prominent problems plaguing theoretical...
For data sets populated by a very well modeled process and by another process of unknown p.d.f., a desired feature when manipulating the fraction of the unknown process (either for enhancing it or suppressing it) consists in avoiding modifying the kinematic distributions of the well modeled one. A bootstrap technique is used to identify sub-samples rich in the well modeled process, and...
An approach to QCD vacuum as a medium describable in terms of statistical ensemble of almost everywhere homogeneous Abelian (anti-)self-dual gluon fields is briefly reviewed. These fields play the role of the confining medium for color charged fields as well as underline the mechanism of realization of chiral $SU_{\rm L}(N_f)\times SU_{\rm R}(N_f)$ and $U_A(1)$ symmetries. Hadronization...
We study scaling properties of the model of fully developed turbulence of a compressible fluid, based on the stochastic Navier-Stokes equation, by means of the field theoretic renormalization group (RG). This model was already considered earlier in [N.V. Antonov, M.Yu. Nalimov, and A.A. Udalov, Theor. Math. Phys., Vol. 110, No. 3, 1997]. The scaling properties in that approach are related to...
In compact stars, nucleons form an interacting multi-fluid system of a neutron superfluid and a proton superconductor. The rotation of the star and the strong background magnetic fields generate superfluid vortices and superconducting flux tubes in the core. Using a field-theoretical model of two coupled bosonic fields with entrainment and density coupling, the phase structure of the system...
We present results from a calculation of the QCD equation of state up
to the sixth order in the baryon, strangeness and electric charge
chemical potentials. As the results depend on three independent chemical
potential, we consider various cases to parametrize the strangeness
and electric charge chemical potentials as a function of the baryon
chemical potential and temperature. Among...
After discussing the OZI suppression of one light meson exchange in the interaction of with isospin I = 1 , we study the contribution of the two-pion exchange to the interaction and the exchange of heavy vectors, J/ψ for diagonal transitions and D* for transitions of to J/ψ ρ. We find these latter mechanisms to be weak, but enough to barely bind the system in J = 2 with a mass around 4000 MeV,...
By β-decay a Neutron transforms into a Proton and emits a Positron and a Neutrino. The latter only interacts weakly. During Neutron Star formations and mergers, we have a high Neutrino flux, which can be measured. Therefore by Neutrino measurement, we can learn about the inner structure of Neutron Star formations and mergers. Because during these processes the matter is dense, we have a back...
The Matrix Element Method (MEM) is a powerful multivariate method allowing to maximally exploit the experimental and theoretical information available to an analysis. The method is reviewed in depth, and several recent applications of the MEM at LHC experiments are discussed, such as searches for rare processes and measurements of Standard Model observables in Higgs and Top physics. Finally, a...
The QCD vacuum is populated by instantons that correspond to the tunneling processes in the vacuum. This mechanism creates the strong vacuum gluon fields. As result, The QCD vacuum instantons induce very strong interactions between light quarks, which was initiall almost massles. Such strong interactions bring about a large dynamical mass $M$ of the light quarks and can bound them to produce...
In this talk we report on two recent works about the $Z_c(3900)$ resonance. A coupled channel T-matrix is used in the description of the $D^*\bar{D}$ and $J/\psi\pi$ spectra in which the $Z_c(3900)$ peak has been seen. The data can be well reproduced in two different scenarios, in which the $Z_c(3900)$ is a resonance or a virtual state. We also put this coupled channel $T$-matrix in a finite...
We summarise recent advances on the description of exotic and excited states
using an approach to QCD via Dyson-Schwinger and Bethe-Salpeter equations.
We discuss first steps in the calculation of (quenched) glueball states, explain
in more detail methods and results to extract the spectrum of four-(anti-)quark
states from the four-body Faddeev-Yakubovski equation and present first...
Accepting that there is a mass gap above the electroweak scale, electroweak effective theory (EWET) is an appropriate tool to describe this sector, where only the Standard Model fields are taken into account. Since the EWET couplings contain information on the unknown high-energy dynamics, we consider a generic strongly-coupled scenario of electroweak symmetry breaking, where the known...
Main physics goals of the NA61/SHINE programme on strong interactions
are the study of the properties of the onset of deconfinement and the search
for signatures of the critical point of strongly interacting matter. For these goals the scan through two dimensional phase diagram (T-$\mu_B$) is being performed
at the SPS by measurements of hadron production in nucleus-nucleus collisions
as...
None
In my talk, I will present an overview of on-going machine-learning software development in particle physics, in particular focusing on the recent developments related to the Toolkit of Multivariate Analysis (TMVA). I will additionally summarize the current activities of the Inter-experimental Machine Learning Working Group (IML).
In QCD many quantities, like bound states properties or positions of (pseudo-)phase transitions, can be calculated from the correlation functions of quarks and gluons. The correlation functions themselves can be determined non-perturbatively from various sets of functional equations. Here, truncated Dyson-Schwinger equations are employed for the study of the gluonic sector of QCD at non-zero...
Short range particle repulsion is rather important property of the hadronic and nuclear matter equations of state. I present a novel equation of state which is based on the virial expansion for the multicomponent mixtures with hard core repulsion.
The suggested equation of state explicitly contains the surface tension which is induced by particle interaction. At high densities such a surface...
A new analytic non-perturbative, gauge invariant exact solution to QCD is derived. This solution is then compared with experimental data. Specifically high-energy proton-proton elastic scattering at ISR energies. A first proposal for LHC energies is examined also.
We present a new technique to resum analytically large threshold logarithms in heavy quark decay which simplifies multi-scale problems and apply it to the B -> X_s gamma decay
An efficient way to study the QCD phase diagram at small finite density is to extrapolate thermodynamical observables from imaginary chemical potential. In this talk we present results on several observables for the equation of state to order (muB/T)^6. The observables are calculated along the isentropic trajectories in the (T, muB ) plane corresponding to the RHIC Beam Energy Scan collision...
The flexibility of the Relativistic Heavy Ion Collider (RHIC) facility to collide atomic nuclei of different sizes over a wide range of
energies provides the experimental leverage necessary to clarify the nature of QCD matter. RHIC launched a multi-step experimental program to investigate the phase diagram of strongly interacting nuclear matter. The exploratory phase I of the Beam Energy Scan...
While the current heavy-ion programmes at RHIC and LHC address QCD matter at the hoghest achievable energies, but vanishing net-baryon densities, nuclear collisions at lower energies give access to matter at large baryo-chemical potential. This region of the QCD phase diagram is hardly accessible by first-principle QCD calculations, but QCD-inspired models suggest it to have a rich structure....
The main goal of physics program at the Nuclotron-based Ion Collider fAcility
(NICA) accelerator complex is a search for the possible mixed phase of quark matter and
baryon rich hadronic matter as a consequence of the first order phase transition.
Fixed target experiment Baryonic Matter at Nuclotron (BM@N) and collider experiment Multi Pupose Detector (MPD) at the NICA facility will work...
In a few years — right before and after the November Revolution of 1974 — particle physics, with full wind in its sails, changed very significantly. Quarks, somewhat reluctantly invented during the 1963/64 Christmas holidays, turned out to be for real. QCD and the rest of the Standard Model evolved from being considered a tropical disease affecting an overwhelmed minority of field theorists to...
We study the QGP equation of state using finite quark mass with the finite size effect by taking into account of Multiple Reflection Expansion (MRE). The quark mass improves the calculation of free energy in the formation of QGP droplet. Finally, the model results provide QGP equation of state that matches well with the lattice results.
We discuss how the thermal ground state of an SU(2) Yang-Mills theory in its deconfining phase is composed of Harrington-Shepard (HS) (anti)calorons that are subject to deformation due to overlapping and static peripheries. The construction first performs a spatial coarse-graining over the central regions for HS (anti)calorons in isolation -- a unique process which determines the temperature...
$\eta_c$ production at the LHC and indications on the understanding of $J/\psi$
In this talk, we will review a number of recent ideas⋆ put forward in favour of a fixed-target programme at the LHC - AFTER@LHC. By extracting the beam with a bent crystal or by using an internal gas target, the multi-TeV LHC beams allow one to perform the most energetic fixed-target experiments ever and to study with high precision pp, pd and pA collisions at $\sqrt{s_{NN}}$=115 GeV and Pbp...
The dual parametrization of of generalized parton distributions (GPDs) and the
Mellin-Barnes integral approach represent two frameworks for handling the double
partial wave expansion of GPDs in the conformal partial waves and in the cross-channel
${\rm SO}(3)$ partial waves. We explicitly show the complete equivalence of these two independently developed GPD representations. This provides...
We compute for first time the spectrum of the Bethe-Salpeter equation, for a system composed of two bosons exchanging a massive scalar. The ladder approximation for the kernel is used. This study is performed directly in the Minkowski space by using the Nakanishi representation of the Bethe-Salpeter amplitude and the projection onto the null plane or light-front projection. The eigenvalues,...
The anomalous magnetic moment of the muon, defined as the fractional difference of its gyromagnetic ratio from the naive value of 2, has been measured with an impressive accuracy of 0.54 parts per million in experiment (BNL E821), thus providing one of the most stringent tests of the Standard Model. Intriguingly, the experimentally measured anomaly disagrees by around 3 standard deviations...
Recent $\eta_c$ hadroproduction data provided an excellent opportunity for the determination of the color-octet matrix elements for the charmonia production. This talk will present the theoretical results for the $\eta_c$ hadroproduction versus the LHCb data and its impact on the $J/\psi$ production and polarization.
Axial charge imbalance is an essential ingredient in novel effects related to the chiral anomaly like the chiral magnetic effect. In non-Abelian plasma with chiral fermions, local axial charge can be generated either by topological fluctuations of the medium or by usual thermal fluctuations. We show how local topological domains in the Quark Gluon Plasma lead to the dynamical generation of an...
The presence of collective expansion in small collision is discussed. Approaches based on relativistic hydrodynamics are compared to existing data. Possibilities to study fluctuations in the interaction region in small collision systems are described.
