We will present our newly developed DREENA framework - a numerical implementation of our dynamical energy loss formalism that allows generating predictions for a wide range of high pt observables, centralities, collision energies, different experiments and collision systems. To demonstrate its utility, we will first show that our postdictions agree well with a wide range of available high pt...
The research for hypernuclei and their production mechanisms open new
opportunities for nuclear/particle physics and astrophysics. The hyperons
influence many nuclear properties in finite nuclei and in neutron stars
(infinite nuclear matter). In particular, hypernuclei allow to explore
the many-body aspects of the strong three-flavor interaction at low energies.
We review the main...
Heavy quarks are initially produced in nuclear collisions and the number is conserved during the evolution of the system. We establish a sequential coalescence model with charm conservation and apply it to charmed hadron production at RHIC and LHC energies. The charm conservation enhances the earlier formed hadrons and reduces the later formed ones, which leads to a Ds/D0 enhancement and a...
Strangeness production in nucleus-nucleus collisions has been a subject of studies over 40 years. It has played a key role in a search for the quark-gluon plasma and the onset of deconfinement in the collisions. Here of particular importance are results of the NA49 and NA61/SHINE experiments at CERN SPS and the STAR BES experiment at RHIC. They have conducted measurements of hadron production...
Due to their large masses, the interactions of heavy quarks with the quark-gluon plasma (QGP) may be different from those of light quarks. The lightest charm baryon is the $\Lambda_{c}^{+}$, composed of a charm quark and two light quarks. Measurements of $\Lambda_{c}^{+}$ production in both pp and PbPb collisions can provide important inputs to the understanding of heavy quark transport in the...
The production of low-mass dielectrons is the most promising tool for the understanding of the chiral symmetry restoration and of the properties of the Quark-Gluon Plasma (QGP) created in heavy-ion collisions. At low invariant mass, the dielectron production is sensitive to the properties of vector mesons in the medium related to the chiral symmetry restoration. In the intermediate-mass...
We investigate whether the quark gluon plasma (QGP) is created in small colliding systems focusing on hadron production mechanisms.
Recently the ALICE Collaboration reported strangeness enhancement in small colliding systems. The yield ratios of (multi-)strange hadrons to charged pions in various colliding systems show the monotonic increase and scaling with multiplicity [1]. Motivated by...
The experimental investigation of the low-energy negatively charged kaons interaction with the nuclear matter is very important to understand the strength of the K-nuclei interaction and to provide essential input for understanding of the non-perturbative QCD in the strangeness sector. It has strong consequences in various sectors of physics, like nuclear and particle physics as well as...
Starting from the investigation on recent experiments about charmed hadrons, e.g., nuclear modification factor ratios between charmoinum states and measurements of doubly charmed hadrons, we discuss the production of those charmed hadrons by recombination in heavy ion collisions. We adopt the coalescence model, and evaluate transverse momentum distributions of not only charmonium states but...
It is entirely plausible that during the primordial quark – hadron transition, microseconds after the Big Bang, supercooling takes place accompanied by mini inflation leading to a first – order phase transition from quarks to hadrons. The relics, in the form of quark nuggets consisting of Strange Quark Matter under certain circumstances survive.
It is conjectured that color confinement turns...
Light flavor hadrons are copiously produced in hadronic and heavy-ion interactions and bring a wealth of information about properties of the produced medium and reaction dynamics. Having different masses, quark content and lifetimes, light flavour hadrons do not only serve as general observables in the soft sector, but also play an important role as high transverse momentum probes and...
Heavy flavour probes provide important information about the in-medium properties of the quark gluon plasma produced in heavy-ion collisions. In this work, we investigate the effects of (2+1)d event-by-event fluctuating hydrodynamic backgrounds on the nuclear suppression factor and momentum anisotropies of heavy flavour mesons and non-photonic electrons [1,2]. Using the state-of-the-art D and...
Compact star observables are robust and not in one-to-one functional relationship with the microscopical parameters of the applied equation of state. This, the Masquarade problem, which means many types of equation of state parametrization and various parameter settings lead to the same macroscopic observation parameters.
So far we investigated a one-fermion-one-boson model with a simplistic...
The hadronization process of heavy hadrons with bottom and charm quarks, especially for baryons $\Lambda_c$ and $\Lambda_b$, in a dense QGP medium is largely not understood.
We present predictions obtained with a coalescence plus fragmentation model, for $D^0$, $D_s$, $\Lambda_c$, B and $\Lambda_b$ spectra, the related baryon to meson ratios and the $D_s/D^0$ ratio, both at RHIC and LHC...
A rich set of open heavy flavour states is observed by LHCb in pPb collisions collected at 5 and 8.16 TeV nucleon-nucleon center-of-mass energies. Thanks to the LHCb forward acceptance that is complementary to general purpose detectors, heavy-flavor hadrons can be studied down to zero pT. Presented in this talk is the measurements of production of beauty hadrons and open charm states...
The ALICE experiment is dedicated to the study of strongly interacting matter at the extremely high temperatures and energy densities reached at the LHC. Its excellent tracking and particle-identification capabilities allow characterising the hot nuclear matter via detailed measurements of particle production in nucleus-nucleus collisions. In addition, the study of proton-nucleus collisions...
In hadronic collisions, beauty quarks are produced in hard scattering processes with large momentum transfer. Their production provides a very important test of perturbative QCD calculations in pp collisions. In heavy-ion collisions, the measurement of beauty-hadron production is a unique tool to investigate the properties of the Quark-Gluon Plasma. In particular, beauty quarks, being four...
We performed state-of-the-art QCD effective kinetic theory simulations of chemically equilibrating QGP in longitudinally expanding systems. We find that chemical equilibration takes place after hydrodynamization, but well before local thermalization. By relating the transport properties of QGP and the system size we estimate that hadronic collisions with final state multiplicities dNch/dη≳10^2...
Charm quarks are a powerful probe of the Quark-Gluon Plasma (QGP) formed in high energy heavy-ion collisions. Produced in hard scattering processes on a timescale shorter than the QGP formation time, they experience the whole system evolution. There have been extensive researches regarding the production of charm mesons, such as D$^0$, D$^+$, D$^{*+}$, in heavy-ion collisions to investigate...
Merging binaries of neutron stars are not only strong sources of gravitational waves, but also have the potential of revealing states of matter at densities and temperatures not accessible in laboratories. A crucial and long-standing question in this context is whether quarks are deconfined as a result of the dramatic increase in density and temperature following the merger. I will present the...
Strangeness production has long been considered a golden observable to characterize the chemical composition of the deconfined state of matter produced in heavy ion collisions. One of the key results of the LHC Run 1 was the observation of an enhanced production of strange particles in high multiplicity pp and p-Pb collisions at 7 and 5.02 TeV, respectively. In addition, the multiplicity...
Heavy quarks are effective probes of the properties of the Quark-Gluon Plasma (QGP) created in ultra-relativistic heavy-ion collisions. Charm and beauty quarks, due to their masses, are produced in hard scattering processes on timescales shorter than the QGP formation time. They experience the entire evolution of the medium, interacting with its constituents via in-medium gluon radiation and...
We present high statistics data on proton and light nuclei emission from Au+Au collisions at $\sqrt{s_{NN}}$ = 2.4 GeV measured with HADES.
The data are analysed as function of reduced transverse mass $m_t - m_0$ and rapidity $y$ in 4 centrality classes corresponding to the 40$\%$ most central events.
In contrast to higher energies light nuclei are not rare but make up about 30$\%$ of all...
Spin alignment of vector mesons produced in non-central heavy-ion collisions could occur due to the large angular momentum and intense magnetic field expected in the initial stages of these collisions. This phenomenon leads to a non-uniform angular distribution of the decay products of the vector meson with respect to the quantization axis in the rest frame of vector meson. The quantization...
Proton-nucleus collisions at relativistic energy, traditionally regarded as control measurements for heavy ion collisions, are now capturing the attention due to the recent experimental observations at RHIC and LHC that indicate the formation of quark-gluon plasma even in these small systems. In the early stage of relativistic heavy ion collisions extremely intense magnetic fields, with a...
The role of kinetic and hydrodynamic degrees of freedom in generation of vorticity and hydrodynamic helicity is considered. The structure of emerging vortex sheets and quadrupole vorticity patterns is studied in detail. The emergence of compressibility in the framework of kinetic description is explored. The transition of vorticity and hydrodynamic helicity to polarization of quarks and...
The heavy-flavour particles are produced in the earlier stage in heavy-ion collision and experience the full evolution of the QGP medium. The measurement of D mesons could provide us important inputs for flavour and charge dependent transport properties. On the other hand, with abundant strange quarks presented in heavy-ion collision, the $D_{S}^{+}$ production is expected to be enhanced...
The high energy pp, p-Pb, and Pb-Pb collisions at the LHC offer a unique tool to study the production of light (anti-)nuclei. The study of the production yield of (anti-)nuclei in heavy-ion collisions at the LHC energy probes the late stages in the evolution of the hot, dense nuclear matter created in the collision and serves as baseline for the search of exotic multi-baryon states.
The same...
The directed flow, vorticity and polarisation of Lambda were calculated
within the UrQMD model for intermediate-centrality A+A collisions at
FAIR and NICA energies. Also, we investigated vorticity and helicity development
of protons and pions in these reactions. The slope of the directed flow $dv_{1}/dy$ at
midrapidity in calculations with and without mean-field potentials is obtained as
a...
The fluctuations of conserved charges – such as electric charge, strangeness, and baryon number – in ultrarelativistic heavy-ion collisions provide insight into the properties of the quark-gluon plasma and the QCD phase diagram. They can be related to the higher moments of the multiplic-
ity distributions of identified particles such as pions, kaons, protons, and lambda baryons. In this talk,...
ALICE has performed several measurements aimed at understanding the heavy-ion-like patterns observed in small collision systems. New approaches can be helpful to clarify particle production mechanisms in pp collisions, as well as the similarities observed among the systems created in pp, p-A and A-A collisions.
In this talk we report on charged particle transverse momentum distributions as a...
We study the propagation of heavy quarks (HQ), charm and bottom, in the QGP by means of a relativistic Boltzmann transport approach. The non-perturbative interaction between HQs and light quarks is described by means of a quasi-particle approach that permits to have an Equation of State close to lattice QCD and it is able to describe the main feature of the non-perturbative dynamics: the...
Measurements of bottomonium production are reported for the $\Upsilon(1S)$, $\Upsilon(2S)$, and $\Upsilon(3S)$ mesons in pp, pPb and PbPb collisions at 5.02 TeV. The analysis was performed as a function of rapidity and transverse momentum. In addition, the dependence on the event activity and collision centrality is studied in pPb and PbPb collisions, respectively. New results of the upsilon...
We study the dependence of the normalized moments of the net-proton multiplicity distributions on the definition of centrality in relativistic nuclear collisions at a beam energy 7.7 GeV. Using the UrQMD model as event generator we find that the centrality definition has a large effect on the extracted cumulant ratios. Furthermore we find that the finite efficiency for the determination of the...
To observe a possible vortical structure of the system created in relativistic heavy-ion collisions,
the spin directions of produced particles with respect to the total angular momentum need to be measured. The $\Lambda$ hyperon is a good candidate to look for a possible spin polarization. Due to the parity violation of the weak interaction, the daughter proton is predominantly emitted in the...
At RHIC energies, charm quarks are primarily produced at early stages of ultra-relativistic heavy-ion collisions, in hard partonic scatterings. This makes them an ideal probe of the Quark-Gluon Plasma (QGP) since they experience the whole evolution of the hot and dense medium. STAR is able to measure the production of charm quarks and their interaction with the QGP through direct...
The ALICE experiment is dedicated to the study of the quark-gluon plasma (QGP) formed in heavy-ion collisions. To investigate the initial state and space-time evolution of the medium, direct photons are excellent probes because they don't interact strongly. In particular, the low $p_{\rm T}$ thermal photon spectrum and flow measurements carry information about the medium's temperature and...
Beauty quarks are considered to be one of the golden probes of the strong interacting medium created in heavy-ion collisions as they are mainly produced via initial hard scatterings and strongly interact with the medium. They are sensitive to the transport properties of the medium and may interact with the QCD matter differently from light quarks. High-precision measurement of B mesons will...
Relativistic Hydrodynamics has been very successful in describing the space-time evolution of hot and dense QCD matter created in high energy heavy ion collisions. We employ quasiparticle kinetic models to derive a causal theory of relativistic hydrodynamics which can incorporate any equation of state in a thermodynamically consistent framework. To this end, the phase space distribution...
Heavy quarks (charm and beauty) are effective probes to test perturbative QCD-based calculations in pp collisions and to study cold nuclear matter (CNM) effects such as gluon saturation, shadowing, kT broadening and energy loss in CNM in p-Pb collisions. In addition, the positive elliptic flow ($v_2$) of open heavy-flavour particles observed in semi-central Pb-Pb collisions at LHC energies...
The modifications of basic properties of hadrons inside a hot and dense nuclear matter are a consequence of the partial restoration of the chiral symmetry and are an intensively studied topic for the last 30 years [1]. Whereas the effects for K$^+$ and K$^0_S$ appear to be theoretically more straightforward and experimentally established [2,3], it seems not to be the case for K$^–$. A series...
Suppression of the production yield of $\Upsilon$ states in heavy-ion collisions relative to expectation from p+p collisions is a tool for studying the properties of quark-gluon plasma. Such suppression is expected to be caused by Debye-like screening of color charges happening at a high temperature in the plasma. In order to correctly interpret this effect, the $\Upsilon$ production mechanism...
The expected increase in the integrated luminosity foreseen for the LHC Runs 3 and 4, combined with the performance of the upgraded ALICE detector, will allow for the measurement of the production of rare light-flavour probes such as (anti)nuclei and exotic states. Not only are these important probes of the system created in high-energy proton-proton (pp) and heavy-ion collisions, but also...
The expansion of the matter formed in nucleus-nucleus collisions at relativistic energies produces a collective transverse flow. This flow is the response to the density gradients in the initial fireball. It is azimuthally asymmetric because the initial fire-ball is anisotropic and contains hot spots. These inhomogeneities are of particular interest for two reasons. They reflect the poorly...
The study of the interaction of heavy quarks with the constituents of the medium created in heavy-ion collisions provides important information about the characteristics of the Quark-Gluon Plasma (QGP). The production of heavy quarks occurs prior to the formation of the QGP, implying that they experience the entire evolution of the system. To infer the properties of the partonic interactions...
The ALICE experiment at the Large Hadron Collider (LHC) is dedicated to study the prop- erties of the Quark-Gluon Plasma (QGP), a de-confined partonic state of strongly-interacting matter formed in relativistic heavy-ion collisions. Heavy quarks (charm and beauty), produced by parton-parton hard scatterings in the early stages of such collisions, are considered to be effective probes to study...
One of the most common assumptions when calculating radiative energy loss of high $p_{\perp}$ particles in quark-gluon plasma is the soft-gluon approximation, which considers that initial parton losses only a small amount of its energy via gluon's bremsstrahlung. Despite its convenience, the approximation sustainability was questioned by the reported notable radiative energy loss within...
Strangeness enhancement has been observed in high-multiplicity proton-proton (pp) collisions at the LHC for several multi-strange hadrons and shown to be in remarkable agreement with the measurements performed in p-Pb collisions. Resonance particles with different lifetimes can provide an interesting insight into the properties of the hadronic phase in high-multiplicity proton-proton (pp)...
HADES provides a large acceptance combined with a high mass-resolution and therefore allows to study dielectron and hadron production in heavy-ion collisions with unprecedented precision. The high statistics measurements of flow coefficients for protons, deuterons and tritons in Au+Au collisions at 1.23 AGeV (performed with the HADES experiment at SIS18/GSI) are presented here. In addition to...
We report on results of fitting pt spectra of identified particles with the blast-wave model with included resonances and chemical potentials according to the model of partial chemical equilibrium. Bayesian technique with Gaussian emulator is used in the fitting procedure. Spectra from the RHIC BES programme and LHC are included in the analysis. For central collisions, the freeze-out...
Heavy quarks are produced in hard scattering processes during the early stages of a heavy-ion collision at ultra-relativistic energies. Their annihilation rate is negligible, and they participate in the whole medium evolution losing their energy via radiative and collisional processes while traversing through the Quark-Gluon Plasma (QGP) formed in such collisions. This allows us to study the...
The novel microscopic n-body dynamical transport approach PHQMD (Parton-Hadron-Quantum-Molecular-Dynamics) extends the established PHSD (Parton-Hadron-String-Dynamics) transport approach by introducing n-body quantum molecular dynamic type propagation of hadrons and by allowing to choose the equations of state with different compression modulus.
We present first results of the study on the...
The BM@N (Baryonic Matter at Nuclotron) is the first working fixed-targeted experiment at the Nuclotron-based Ion Collider fAсility (NICA). The properties of hadrons and formation of (multi-)strange hyperons will be studied at BM@N. Also, the experiment involves the searching of hypernuclei.
In 2018 a new topic was added to the BM@N physics program - the studies of Short Range Correlations...
The Compressed Baryonic Matter (CBM) experiment will access a wide range of physics observables for heavy-ion collisions in the regime of highest net-baryon densities. Two of the core topics of its physics program are on one hand the measurement of dilepton production and on the other hand the study of hypernuclei, which were both not measured before with other experiments in this energy...
We will present our newly developed DREENA framework [1], which allows predicting energy loss of high $p_{\perp}$ partons traversing quark gluon plasma (QGP). DREENA framework is based on state-of-the-art dynamical energy loss formalism, which takes into account finite size medium composed of dynamical (that is moving) constituents. In DREENA-B, this formalism is applied to 1+1D Bjorken medium...
Heavy quarks are produced in the early stages of relativistic heavy-ion collisions via initial hard scatterings. Therefore, they are considered as effective probes of the hot and dense Quark-Gluon Plasma (QGP) formed in such collisions since they witness its full evolution. In pp collisions, the measurement of charm and beauty hadron production cross sections can be used to test our...
The study of hadronic resonance production provides a unique tool to investigate the interplay of re-scattering and regeneration effects in the hadronic phase of heavy-ion collisions. The $\phi$ meson has a longer lifetime compared to other resonances. Thus, it is expected that its production will not be affected by regeneration and re-scattering processes. Measurements in small collision...
The possible correlation between the yield of strange and heavy-flavour particles and the emission of particles in the region outside pN-kinematics (the so-called cumulative region) in pA collisions is studied. The particle production in the cumulative area is considered as a trigger, confirming participation in the process of a dense few-nucleon cluster. From the modern point of view this...
Two-particle correlations can be used to probe the strong interaction between nucleons and multi-strange baryons. We will show measurements of correlation functions of proton-$\Xi^−$ pairs in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV, and proton-$\Omega^−$ pairs produced in high-multiplicity pp collisions at $\sqrt{s}$ = 13 TeV. Utilising newly developed femtoscopic techniques, we will...
The conditions of production and freeze-out of strange particles in central heavy-ion collisions at energies of NICA and FAIR are studied within two microscopic transport models. The system of final particles can be sub-divided into a core, containing the still interacting particles, and a halo with particles already decoupled from the system. In microscopic calculations hadrons are...
When traversing QCD medium, high $p_{\perp}$ partons lose energy, which is measured by suppression, and also predicted by various energy loss models. A crucial test of different energy loss mechanisms is their dependence on the medium temperature. Though it is commonly assumed that this dependence is cubic, different effects such as Debye screenings, finite parton masses, infrared cutoffs,...
In ultra-relativistic heavy-ion collisions, where the formation of a high-density colour-deconfined medium, the Quark-Gluon Plasma (QGP), is expected, heavy quarks are considered as an effective probe for investigating the properties of such a medium. Indeed, they are produced in scattering processes with large momentum transfer in the early stage of the collision and traverse the medium while...
The ALICE Collaboration is preparing a major upgrade of the detector apparatus during the second LHC long shutdown (LS2, 2019-20) in view of the LHC Runs 3 and 4 (2021 to 2029).
The objective of the ALICE upgrade for LS2 is two-fold: i) an improvement of the tracking precision and efficiency, in particular in the low-momentum range; ii) an improvement of the readout capabilities of the...
In the exploration of the phase diagram of strong nuclear force, some of the most intriguing questions are associated with the phase dubbed Quark-Gluon Plasma (QGP). One of the most successful programs in ultra-relativistic nuclear collisions for the studies of QGP properties are the analyses of anisotropic flow phenomenon with correlation techniques. Many additional insights about QGP...
The extreme energy densities reached in Pb-Pb collisions at the LHC lead to a significant production of baryon states. Among the thousands of particles produced, light (anti-)hypernuclei are of special interest: their wide wave function and extremely low binding energy make them sensitive to the conditions created in high energy collisions. The study of their production can shed light on the...
Properties of nuclear matter can be studied by relativistic heavy-ion collisions in high energy experiments like the STAR experiment. One of the methods to learn something about this matter is the femtoscopy, which relies on information carried by the particles produced in the collisions. Using correlation functions, the source parameters, such as space-time characteristics, are provided. The...
The X-ray measurements of kaonic atoms play an important role for
understanding the low-energy QCD in the strangeness sector. The energy shift
and broadening of the lowest-lying states of
such atoms, induced by the kaon-nucleus strong interaction, can be
determined with high precision from atomic X-ray spectroscopy.
Significant achievements have been obtained by the SIDDHARTA experiment...
Low-mass dimuon production, including pairs from the light neutral mesons $\eta$, $\rho$, $\omega$ and $\varphi$, provide key information on the hot and dense state of strongly interacting matter produced in ultra-relativistic heavy-ion collisions. The properties of this medium and its effect on particle production, such as the strangeness enhancement and chiral symmetry restoration, can be...
Hadronization in the non-extensive statistical approach can be described well, by the Tsallis-Pareto based fragmentation Functions [1]. We investigate the mass scaling of the fragmentation parameters in case of massive identified hadron production, like in Ref [2,3]. We present the comparison of global cross section and channel contributions as well.
[1] Á. Takács & G.G. Barnaföldi: ...
The Combustion adiabat (CA) or the Chapman-Jouget adiabat equation can be useful tool to study the phase transition (PT) of a neutron star (NS) to a quark star (QS).
CA is a relation connecting the initial and final state of matter across a shock or a combustion discontinuity, where the initial and the final state belong to different equation of state (EoS).
In this problem we assume the...
In the ultra-relativistic heavy-ion collisions at the CERN Large Hadron Collider (LHC), a state of matter, called Quark-Gluon Plasma (QGP), is created.
Heavy quarks, like charm and beauty, are a powerful tool to investigate the medium formed in these collisions. They are produced in hard partonic scattering processes, which occur on a timescale shorter than the QGP formation time. They...
Open-charmed mesons are unique tools to study the properties of the Quark-Gluon Plasma (QGP) formed in ultra-relativistic nucleus-nucleus collisions. Charm quarks, due to their large mass, are produced in hard partonic scattering processes in the initial stages of the collision. Therefore, they experience all the phases of the QGP evolution propagating through the medium and losing energy...
The Quark-Gluon Plasma (QGP) is a deconfined state of strongly-interacting matter that is produced at the Large Hadron Collider (LHC) via ultra-relativistic heavy-ion collisions. The QGP properties can be investigated by studying the kinematic features of final-state hadrons containing charm or beauty quarks. Heavy quarks are mainly produced in hard scattering processes among partons, that...
Electroweak bosons are created in the hard scattering processes at the initial stage of heavy-ion collisions and they are insensitive to the presence of the strongly-interacting medium. This makes them clean probes of the initial-state effects in heavy-ion collisions, such as the nuclear modification of the Parton Distribution Functions (nPDFs). Furthermore, their measurement in heavy-ion...
Short-lived resonances play an important role to understand the mechanism of particle production and the hadronic phase properties of heavy-ion collisions. Resonance yields are modified due to the interaction of their decay daughters within the hadronic medium via the processes like re-scattering and regeneration. p-Pb collision is a suitable system to study the multiplicity dependence of the...
Heavy quarks (charm and beauty) are produced in the early stages of hadronic collisions via hard scattering processes and therefore are efficient probes to study the properties of the Quark-Gluon Plasma produced in heavy-ion collisions at the LHC. Charged-particle multiplicity gives information on the global characteristics of the event and can be exploited to investigate the possible...
J/$\psi$ mesons have long been proposed as ideal probes capable of providing evidences of the formation of Quark--Gluon Plasma (QGP) in ultra-relativistic heavy-ion collisions. Various Cold Nuclear Matter (CNM) effects are however expected to affect J/$\psi$ production in addition to the modifications due to the presence of the QGP, and the study of p--Pb collisions represents a crucial tool...
The study of production of particles which contain heavy quarks (charm and beauty) provides an exceptional tool to investigate the characteristics of the hot and dense QCD medium, the Quark-Gluon Plasma (QGP), created in ultra-relativistic heavy-ion collisions. In particular, heavy-flavour measurements allow one to study the basic properties of this medium, like its energy density, and to...
Short-lived resonances are powerful probes to understand the hadronic phase in ultra-relativistic heavy-ion collisions, due to their lifetimes of $\sim$10 fm/c, comparable to the time span between chemical and kinetic freeze-out. The measurements of short-lived resonances in pp collisions provide the baseline for heavy-ion collisions measurement. In this respect, we present the multiplicity...
In the ultra-relativistic heavy-ion collisions provided at the LHC nuclear matter undergoes, under extreme conditions of high temperature and high energy density, a transition to a phase in which quarks and gluons are deconfined: the Quark-Gluon Plasma (QGP). Unlike up and down quarks, which form ordinary matter, strange quarks are not present as valence quarks in the initial state and they...
Heavy-flavour production studies in pp collisions, besides providing the necessary baseline for measurements in Pb$-$Pb collisions, constitute a precision test of perturbative QCD calculations. In complex systems such as p$-$Pb collisions, it gives insights into the cold nuclear matter (CNM) effects and also characterizes the nuclear parton distribution functions in the low-$\it{x}$ region,...
Multipomeron model for strange particle production in heavy-ion collisions
G. A. Feofilov, V. N. Kovalenko, A. M. Puchkov, F. F. Valiev
(Saint-Petersburg State University)
The generalized multi-pomeron exchange model \cite{1} - \cite{5} is proposed for the production in high energy heavy-ion collisions of hadrons containing heavy quarks. The main feature of this approach is the effective...
Heavy ions collisions, astronomical observations of neutron stars and their collisions, ab-initio lattice QCD calculations cover only small fractions of QCD phase diagram, leaving the phase structure of QCD still unclear. We propose a unified flavour SU(3) phenomenological model for the QCD thermodynamics with all known hadrons and u,d, and s quarks as degrees of freedom. The model...
The heavy-flavor quarks (charm, beauty) play an important role in probing the Quark-Gluon Plasma (QGP) formed in the heavy-ion collisions. They are produced in hard partonic scattering processes, and have shorter formation time than the QGP. As a result, they experience all the phases of the plasma evolution propagating through the QGP and losing energy interacting with its constituents....
We propose to use the entropy-per-baryon number ratio as a clear signal for a first-order phase transition in heavy-ion collisions. Our study uses the chiral fluid dynamics model, coupling the nonequilibrium dynamics of the chiral order parameter to an expanding quark fluid. As the system is driven out of equilibrium, dissipation and noise lead to a significant increase in entropy during the...
The coherent inelastic processes of the type $a \rightarrow b$, which may take place in the interaction of hadrons and $\gamma$ quanta with nuclei at very high energies (the nucleus remains the same, and its quantum state does not change), and - in particular - may lead to the production of strange and heavy-flavor mesons and baryons, are theoretically investigated. For taking into account the...
The phenomenological structure of inclusive cross-sections of the production of two neutral $K$ mesons in hadron--hadron, hadron--nucleus and nucleus--nucleus collisions is theoretically investigated taking into account the strangeness conservation in strong and electromagnetic interactions. Relations describing the dependence of the correlations of two short-lived and two long-lived neutral...
The study of open charm meson production provides an important tool for detailed investigations of the properties of hot and dense matter formed in nucleus-nucleus collisions. In particular, charm meson data is of vivid interest in the context of the phase-transition between confined hadronic matter and the quark-gluon plasma as well as it is needed for interpretation of data on J/$\psi$ ...
The QCD phase transition is studied within the thermodynamic geometry. Through the definition of a metric in the thermodynamic space, one builds a scalar thermodynamic geometry curvature, $R$, in the usual way and investigates the nature of the interactions. $R$, indeed, reflects some important features of the system: e.g. the so-called interaction hypothesis, $|R|\sim \xi^d$, where $\xi$ is...
When partons traverse the Quark-Gluon Plasma (QGP), they lose energy via collisional and radiative processes. This manifests in a suppression of the measured jet yield and a modification of the jet fragmentation pattern in heavy-ion collisions relative to proton-proton collisions, for which no QGP is expected to form. The amount of energy that is lost is expected to depend on the respective...
The behavior of strange matter in the frame of the SU(3) Polyakov-loop extended Nambu-Jona-Lasinio model is considered. We discuss the appearance of a peak in the ratio of the number of strange mesons to non-strange mesons known as the "horn". We showed that the rise in the ratio $K^+/\pi^+$ appears in PNJL model when we build the $K^+/\pi^+$ ratio along the phase transition diagram. We...
The yields of strange hadrons: $K_s^{0}$ -meson, $\Lambda^-$ and $\bar{\Xi}$ -hyperon produced in proton-proton ($pp$) and proton-nucleus ($pPb$) collisions at $\sqrt{s_{NN}}= 7 \,TeV$ (in rapidity interval of $|y| < 2$ and traverse momentum range of $0 < p_{T} < 10 \, GeV/c$) as a function of $p_T$ are presented. The simulation codes, $EPOS 1.99$, $EPOS-LHC$ and $QGSJETII-04$ are used as...
At the Large Hadron Collider light (anti-)nuclei are significantly produced in proton-proton
(pp), proton-lead (p-Pb) and lead-lead (Pb-Pb) collisions.
The production mechanism of light (anti-)nuclei is an open question in high energy
physics. The measurement of the production spectra and yields allows to improve our
understanding of the late stages in the evolution of high energy collisions....
Hadronic resonances with lifetimes of a few fm/$c$, shorter than or comparable to the timescale of the fireball evolution are sensitive probes of the dynamics and properties of the medium formed after the hadronisation of the QGP. Because of their short lifetimes, they can decay within the hadronic medium, which can alter or destroy the correlation among the decay daughters via interactions...
Transport properties of the quark-gluon plasma in a hot and dense QCD medium have been studied. We have calculated transport coefficients for massive interacting quasi-particles with non-zero widths described by the Dynamical Quasi-Particle Model(DQPM). The DQPM enable to calculate the quark and gluon collisional interaction rates using the cross-sections. The shear and bulk viscosities have...
Due to the high particle multiplicities produced in Pb-Pb collisions, low-energy jets are difficult to be reconstructed using standard jet algorithms. Two-particles correlations in $\Delta\eta$ and $\Delta\varphi$ can instead be used to study jets, their properties and their particle composition. In this work, two-particle correlations between a high-momentum $K^{0}_{S}$ meson, $\Lambda$...
We investigate the production of Ξ(1820) baryons in pp collisions at 13 TeV by reconstructing their Λ-Κ decays. Recent lattice calculations on parity doubling indicate that the masses of negative-parity particles, such as Ξ(1820), may decrease at high temperatures, while the masses of positive-parity partners, i.e. the Ξ(1530), do not. Furthermore, the lifetime of the Ξ(1820) is short enough...
The search for the QCD critical point is one of the major goals in current and future heavy-ion collision experiments. The matter created in such collisions is spatially finite, evolves highly dynamically, and near the critical point homogeneous temperature distributions may be expected at most in regions of a couple of fm. Moreover, to observe fluctuations for a globally conserved order...
We present our results on the cross-correlators of baryon number $B$, electric charge $Q$ and strangeness $S$, obtained from lattice QCD simulations, and we compare them to the predictions of the Hadron Resonance Gas (HRG) model. We discuss possible comparisons to the available experimental results and we suggest additional measurements to bring the data closer to the theoretical calculations.
Quarkonium states produced in heavy-ion collisions serve as essential probes when studying the Quark-Gluon Plasma (QGP). In particular, suppression of quarkonium production in the QGP medium due to the color screening effect has been proposed as a direct signature of the QGP formation. However, there are also other phenomena, such as cold nuclear matter effects and regeneration, which can also...
The NA61/SHINE detector is facing major upgrade process during Long Shutdown 2
period (2019-2021). Which is required to fulfill all assumptions of the open charm
measurement program. The main purpose of the upgrade is to increase the readout
rate by factor 10 and increase acceptance in the high density tracks environment.
The following elements of the detector are parts of the upgrade:...
Studying the QCD phase structure of the strongly interacting matter is one of the primary goals of relativistic heavy-ion collision experiments. The higher moments of conserved quantities for strong interaction such as net charge, net baryon and net strangeness are proposed to be sensitive observables for search of the QCD critical point and the phase transition between quark-gluon plasma and...
We present LHCb results on quarkonia production in proton-lead collisions, using the data collected in 2016 at 8.16 TeV nucleon-nucleon centre-of-mass energy, in the forward region (pseudorapidity between 2 and 5), covering forward (pPb configuration) and backward (Pbp configuration) rapidities. Measurements include charmonia, where the prompt and from-b-decay components are disentangled, and...
The measurement of the hyper-triton lifetime with the ALICE detector at the LHC is presented to address one of the open key question of hypernuclear physics: the hyper-triton lifetime puzzle.
The Pb-Pb dataset collected during the LHC Run 2 at $ \sqrt{s_{\rm NN}}$ = 5.02 TeV allows for a systematic study of light (anti-)hypernuclei production in heavy-ion collisions, in particular, for the...
The phase I RHIC beam energy scan program (BES-I) has provided promising hints in the search for a first-order transition in the QCD phase diagram and the turn-off of QGP signatures at collision energies below 20 GeV.
Several observables warrant closer investigation during the beam energy scan phase II program (BES-II) that covers the center-of-mass energy range 7.7 GeV to 19.6 GeV in...
ALICE (A Large Ion Collider Experiment) is the CERN LHC experiment optimized for the study of the strongly interacting matter produced in heavy-ion collisions and devoted to the characterization of the quark-gluon plasma. Data were collected during LHC Run 1 and Run 2 in lead-lead, proton-lead and proton-proton collisions at several energies.
To achieve the physics program for LHC Run 3,...
The QCD equation of state at zero and finite baryon densities is considered in the
framework of a Hagedorn bag-like model with a crossover transition from hadronic matter to quark-gluon plasma. The model, augmented with non-zero masses of quarks and gluons in the bag spectrum, provides a fair quantitative description of lattice data on thermodynamic functions, the (higher-order) fluctuations...
J/$\psi$ production provides a particular sensitivity to the medium, which can be produced in heavy-ion collisions at ultrarelativistic energies as delivered by the LHC. The vacuum production is modeled by a reference measured in proton-proton collisions and potential initial-state effects can be constrained using p-Pb collisions in the same collision-energy regime.
In this contribution...
We present the novel microscopic n-body dynamical transport approach PHQMD
(Parton-Hadron-Quantum-Molecular-Dynamics) for the description of particle production and cluster formation in heavy-ion reactions at relativistic energies. The PHQMD extends the established PHSD (Parton-Hadron-String-Dynamics) transport approach by replacing the mean field by density dependent two body interactions in...
We calculate the mean-over-variance ratio of the net-kaon fluctuations in the Hadron Resonance Gas (HRG) Model for the five highest energies of the RHIC Beam Energy Scan (BES) for different particle data lists. We compare these results with the latest experimental data from the STAR collaboration in order to extract sets of chemical freeze-out parameters for each list. We focused on the...
We present the first determination of the scattering parameters of $\Lambda K$ pairs ($\Lambda K^+$, $\Lambda K^-$, and $\Lambda K^0_{\rm S}$) associated with strong final state interactions. The parameters are extracted from measured femtoscopic $\Lambda K$ correlation functions in Pb–Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV, with the widely used Lednicky and Lyuboshitz model. The...
LHCb has the unique capability to study collisions of the LHC beams on fixed targets. Internal gas targets of helium, neon and argon have been used so far to collect samples corresponding to integrated luminosities up to 0.1 pb-1. An upgraded target, allowing a wider choice of target gas species and to increase the gas density by up to two orders of magnitude, is going to be installed for the...
Signatures of a strongly coupled system of deconfined quarks and gluons have been observed in high energy heavy-ion collisions at RHIC and LHC facilities. A systematic measurement of quarkonia production has been carried out in these experiments and several theoretical models have been proposed to understand the measurements.
It has been argued that the hot QGP medium produced in the...
The measurement of conserved charge distributions have generated considerable interest in understanding the cumulants of conserved quantum numbers in the crossover region of the QCD phase diagram, in particular near a possible critical end point and near a postulated common chemical freeze-out line. Initially net protons and net kaons have been used as proxies for the net baryon and...
The main goal of studying heavy-ion collisions is to understand the properties of the matter under extreme conditions. The spatial and temporal characteristics of particle emission can be extracted using femtoscpy technique. From non-identical particle correlations one can obtain information about asymmetry in emission process between those two kind of particles. Such asymmetry can provide...
The main goal of the CBM experiment at FAIR is to study the behavior of nuclear matter at very high baryonic density. This includes the exploration of the high density equation of state, search for the transition to a deconfined and chirally restored phase, critical endpoint. The promising diagnostic probes for this new states are the enhanced production of multi-strange (anti-)particles. The...
Heavy quarks are produced at the first instant of a nucleus-nucleus collision and therefore are an important tool to study the subsequent high energy-density medium formed in ultra-relativistic heavy-ion collisions. A series of experimental efforts for understanding the properties of the Quark-Gluon Plasma (QGP), a medium consisting of a deconfined state of quarks and gluons, are based...
The NA61/SHINE experimental physics program is focused on searching for the critical point and on the study of the properties of the onset of deconfinement in strongly interacting matter. A scan of the phase diagram of strongly interacting matter is done by changing the energy of colliding ions (from 13A to 150/158A GeV) and by changing the system size (from p+p to Pb+Pb).
The main topic of...
We derive a diffusion coefficient for heavy quarks in a strongly-coupled plasma using the AdS/CFT correspondence. Crucially, unlike some prior calculations, our novel diffusion coefficient does not increase with heavy quark velocity: instead, we find that the effect of momentum fluctuations smoothly interpolates between light and heavy flavours. Taking our diffusion coefficient derivation as...
I present a first-principles description of the system created in relativistic heavy-ion collisions, whose primordial density fluctuations and anisotropy I evaluate in the color glass condensate (CGC) framework of high-energy QCD. Relating the primordial anisotropy of the system to the observed final-state anisotropic flow through a simple linear scaling, I achieve an excellent description of...
The heavy-ion collisions at energies of FAIR and NICA are studied within the microscopic transport models. The whole interaction area is subdivided into the smaller cells. We perform the analysis of the space-time evolution of all particles in all cells, in the T-mu_B and T-mu_S planes, and the analysis in x-t of the finally emitted strange and non-strange particles.
Following the time...
The measurement of the elliptic and the triangular flow of (anti-)nuclei is a powerful tool to have insight into the production mechanisms of particles in heavy-ion collisions.
Namely, it will help to distinguish between coalescence and hydrodynamic models.
The coalescence approach predicts light nuclei formation as the result of coalescence of nucleons which are close enough in the phase...
We present the preliminary results on an anisotropic transverse flow of particles with strange content ($K^0_s$ and $K^+$) in Au+Au collisions at $\sqrt s_\mathrm{NN} = 2.42\,\mathrm{GeV}$ measured with HADES. The strange particle flow in a heavy-ion collision is a good probe for nuclear equation-of-state. Kaon flow was seldom measured at such low centre-of-mass energy region due to...
A study of the production of J/psi mesons in conjunction with jets in pp collisions at sqrt(s) = 8 TeV is presented. The analysis is based on data corresponding to an integrated luminosity of 19.1 fb−1 collected with the CMS detector at the LHC. For events with at least one reconstructed jet in the gluon-dominated central region |etajet| < 1, the angular separation between the J/psi meson and...
The extreme conditions reached in ultra-relativistic heavy-ion collisions at the LHC are expected to produce a state of matter in which quarks and gluons are deconfined, the quark-gluon plasma (QGP). As a consequence, several features, such as elliptic flow and chemically equilibrated particle production, are expected and observed in these collision systems. However, it has to be noted that,...
Heavy quarks (charm and beauty) are produced in hard parton scatterings in the early stage of hadronic collisions. Therefore, they are ideal probes to investigate the properties of the Quark-Gluon Plasma (QGP) produced in ultra-relativistic heavy-ion collisions. Measurements of heavy-flavour jets give a direct access to the initial parton kinematics and can provide constraints for heavy-quark...
A consistent modelling of back reaction of the hydrodynamic medium on the jet evolution is important for understanding the substructure of jets produced in heavy ion collisions. The majority of existing models implement only one-way jet-hydro interaction by coupling jets to a fixed hydrodynamic expansion and not including the energy deposition in the medium itself.
In this talk, we show the...
Relativistic heavy-ion collisions offer a unique opportunity to study the properties of nuclear matter at very high temperature and/or high density. It is believed that resonances (like $K^{*0}$, $\phi$) are excellent probes for the medium created in heavy-ion collisions. Particularly, $K^{*0}$ (lifetime $\sim$ 4 fm/c) and $\phi$ (lifetime $\sim$ 42 fm/c) can be used to study the bulk...
In order to understand strangeness and resonance production mechanisms, one can study the correlations of hadrons with hidden (e.g. the $\phi$ meson) and open strangeness ($K_{S}^{0}$, $\Lambda$ and $\bar{\Lambda}$) in hard (jet) processes and in soft (bulk) processes. Two-particle jet-like angular correlations with $\phi$ mesons in p-Pb collisions probe both the jet and the underlying event...
The CMS Collaboration has a major detector upgrade plan during the long shutdown 3 (LS3) starting in 2019 to prepare the high-luminosity runs. It includes the new tracking system, the muon system, the electromagnetic and hadronic calorimeters, and the trigger system. This upgrade will significantly enhance the physics performance of the CMS detector for not only proton-proton collisions, but...
Measurements of the production of short-lived hadronic resonances are used to probe the properties of the late hadronic phase in ultra-relativistic heavy-ion collisions. Since these resonances have lifetimes comparable to that of the fireball, they are sensitive to the competing effects of particle re-scattering and regeneration in the hadronic gas, which modify the observed particle momentum...
A partial restoration of the chiral symmetry is the fundamental quantum process of interaction of the hadronic matter with the quark-antiquark condensate [1]. According to QCD a particle embedded in a hot and dense hadronic matter should change its basic properties like mass and decay constant with respect to their values in vacuum. Kaons produced in heavy ion collisions around threshold for...
We argue that the existence of an inhomogeneous external magnetic field can lead to radial flow in transverse plane. Our aim is to show how the introduction of a magnetic field generalizes the Bjorken flow. We investigate the effect of an inhomogeneous weak external magnetic field on the transverse expansion of in-viscid fluid created in high energy nuclear collisions. Finally we use the...
