We study the in-medium effects in strangeness production in heavy-ion collisions at (sub-)threshold energies of 1 - 2 A GeV based on the microscopic Parton-Hadron-String Dynamics (PHSD) transport approach. The in-medium modifications of the antikaon ($\bar K = K^-, \bar K^0$) properties are described via the self-consistent coupled-channel unitarized scheme based on a SU(3) chiral Lagrangian...
“Ice in fire” is called the phenomenon that in heavy ion collisions at midrapidity clusters have been observed. Their existence is unexpected because objects with a small binding energy (ice) with respect to the temperature of the expanding fireball (fire) should not be formed at all. Applying the recently advanced PHQMD model, which unites the n-body dynamics of nucleons with the collision...
The short-lived hadronic resonances are used to study the properties of the hot and dense medium produced in relativistic heavy-ion collisions. The resonance lineshapes (masses and widths), yields and mean transverse momenta measured in the hadronic decay channels are sensitive to different stages of the nuclear collisions. Having different masses, strangeness content and baryonic numbers,...
Photons serve as valuable probes of the properties of the hot and dense nuclear matter created in collisions of heavy ions. Thermal photon spectra at RHIC and LHC energies indicate that the temperature of the produced medium far exceeds the temperature of the phase transition to the quark-gluon plasma in lattice QCD calculations. Measurements of thermal photon spectra in heavy ion collisions...
Heavy quarks (i.e, charm and bottom) are produced at the very early stage of high energy nucleon-nucleon and heavy-ion collisions. These heavy quarks are produced mainly through initial hard parton-parton scattering with large momentum transfer (Q$^2$). In relativistic heavy-ion collisions, the heavy
quarks are produced much before the formation of deconfined medium consisting of quarks and...
\begin{document}
\title{Overview of Heavy Ion Results at LHCb}
\author{V. ~Pugatch on behalf of the LHCb Collaboration}
\affiliation{Institute for Nuclear Research \ Nat. Acad. of Sci. of Ukraine}
\address{47, Prospekt Nauki, Kyiv, 03680, Ukraine}
\email{pugatch@kinr.kiev.ua}%e-mail
Overview of recent results on heavy ion collisions explored in collider and fixed target mode in the...
The DAMA/LIBRA experiment (about 250 kg of highly radio-pure NaI(Tl)), is running deep underground at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N.; its main aim is the investigation of Dark Matter (DM) particles in the Galactic halo by pursuing the model independent DM annual modulation signature. The results released so far have been obtained with the data of the first phase of...
The possibility of a dark photon in the sub-MeV mass range which has a kinetic mixing with the Standard Model to be a dark matter candidate is highly constrained due to the stringent limits from astrophysical experiments as well as $\Delta N_{\rm eff}$. We present a particle physics model comprising of two hidden sectors where one hidden sector has a direct kinetic mixing with the SM while the...
We study collective modes in chirally asymmetric and momentum-anisotropic quark-gluon plasma, using a kinetic theory approach which is valid in the quasi-particle regime. We introduce a general ansatz to describe the parton distribution functions, and decompose the polarization tensor in terms of nine independent components. We derive and solve the dispersion equations. We discuss the...
Recent ALICE results on the yield of (multi-)strange particles in pp and p--Pb collisions reveal the possibility that similar strange quark production mechanisms could be present in all collision systems.
The $p_{\rm T}$-dependent baryon-to-meson yield ratio in hadronic and nuclear collisions is sensitive to the collective expansion of the system, the partonic recombination into hadrons, the...
To study physical observables in the HADES experiment, it is extremely important to have
a model that can describe the data well. Recently, the HADES experiment collected
collision data for Au+Au@1.23 AGeV and Ag+Ag@1.58AGeV. One of the important
subsystems of the setup is the forward hodoscope, which measures the spectators charge
(FWALL). The comparisons of the experimental charge...
We calculated four types of vorticities in non-central Au+Au collision at energies $ \sqrt{S_{NN}} $ = 5--200 GeV within the microscopic transport model PACIAE. We find that the initial vorticities show clearly non-monotonic dependence on the collision energies, which is in accordance with a previous study. Our calculation shows that the turning point is around 10-15 GeV for different vorticities.
The existence and location of the QCD critical point is an object of both experimental and theoretical studies. One of the main goals of NA61/SHINE, a fixed-target experiment at the CERN SPS, is the search for the critical point of strongly interacting matter. The comprehensive data collected during a two-dimensional scan in beam momentum (13A-150A GeV/c) and system size (p+p, p+Pb, Be+Be,...
Abstract:
LHC data on the correlations of the elliptic flow of particles at low and high $p_T$ from Pb+Pb collisions at $√s_{NN}$= 5.02 TeV are analyzed in the framework of the HYDJET++ model. This model includes soft and hard components which allows to describe the region of both low and high transverse momenta. The origin of $v_2$ values in different $p_T$ regions is investigated at...
The initial motivation to study d+Au collisions was to study the cold
nuclear matter effects and to use this as a control experiment to better
understand the experimental signatures of Quark Gluon Plasma (QGP) in
heavy ion collisions. From 2013, we have been observing unexpected results
indicating the formation of QGP even in small system collisions.
Suppression in the nuclear...
Heavy quarks are mainly produced at the early stages of relativistic heavy-ion collisions before the formation of the quark-gluon plasma (QGP). Heavy quarks then experience the entire evolution of the QGP medium, and thus are ideal probes of the QGP properties. Measuring the open heavy flavor hadrons and their decayed electrons with different observables provides information for different...
The study of phenomenology of the strong nuclear force (QCD) in High energy collisions of hadrons accessing the data from particle physics colliders is an ongoing research during last two decades. Different phenomenological models along with the event generators are used to reproduce experimental data.
There is confrontation of such model components and experimental data during its validation...
STAR’s beam energy scan program at RHIC provides data on net-proton number fluctuations with the goal to detect the QCD critical point and first-order phase transition. Interpreting these experimental signals requires a vital understanding of the interplay of critical phenomena and the nonequilibrium dynamics of the rapidly expanding fireball. We study these aspects with a fluid dynamic...
We present a study of the average transverse momentum and multiplicity distributions using different Monte Carlo event generators. The sensitivity in these observables to the collective phenomena at the LHC and NICA energies is investigated. Besides, we explore the average transverse momentum as a function of the multiplicity scaled to the transverse collision area, the energy, and entropy...
Going beyond the simplified gluonic cascades, we have introduced both gluon and quark degrees of freedom for partonic cascades inside the medium. We then solve the set of coupled evolution equations with splitting kernels calculated for static, exponentially expanding and Bjorken media to arrive at medium-modified parton spectra for quark and gluon initiated jets. For our calculations, we have...
The search for the expected first-order phase transition between the hadronic matter and quark-gluon plasma and the corresponding critical endpoint is an active field of research. One of the main approaches to study this problem is based on fluctuations of e.g. net-baryon number, net-charge, or net-strangeness number measured in relativistic heavy-ion collisions. The cumulants are commonly...
Conventional Boltzmann transport equation (BTE) has an exponential stationary solution. While studying the equilibrium distribution of the heavy quarks in the quark-gluon plasma using the Fokker-Planck equation (obtained from the conventional BTE), Rafelski and Walton in 2000 showed that this distribution is rather power-like. However, there exists a generalized Boltzmann transport equation...
The current work is used to explore the structure of hot and dense system quark gluon plasma (QGP) in order to deal with the dynamics of quarks and gluons in magnetized field. Since a huge and intense magnetic field is expected to be produce at RHIC and LHC, we calculate the equation of states (EoS) in the presence of time dependent magnetic fields with the medium effects of quarks and gluons...
At RHIC energies, charm quarks are primarily produced in hard partonic scatterings at early stages of ultra-relativistic heavy-ion collisions. This makes them an ideal probe of the Quark-Gluon Plasma (QGP), as they experience the entire evolution of this hot and dense medium. STAR is able to measure the production of charm quarks and their interaction with the QGP through direct reconstruction...
In this work, we study the non-extensive Tsallis statistics and its applications to QCD and high energy physics. In particular, we present recent investigations on the power-law distributions arising in high energy physics experiments focusing on a thermodynamic description of the system formed, based on Tsallis statistics which could explain this power-law behavior. The possible connections...
In the next years the BM@N experiment at the Nuclotron at JINR in Dubna will carry out the physics program with heavy ion beams with energies up to 3.8 AGeV and intensities up to $2$$\cdot$$10^6$ ions/s. The experiment is devoted to measure observables sensitive to the equation of state of dense baryonic matter. To meet this goal the existing BM@N set-up will be upgraded with fast hybrid...
The magnetic field and medium effects on electrical and hall conductivities of a hot and magnetized pion gas has been studied. The conductivities has been evaluated using kinetic theory approach in the ambit of relaxation time approximation. Thermal field theoretical techniques has been used to evaluate the dynamical input to these conductivities.
We study one of the important indirect signature of quark gluon plasma as electromagnetic signals. This work is carried out using a phenomenology of heavy-ion collisions in the limit of high temperature and chemical potential. The gamma gamma production rate is shown for lowest order process incorporating quark mass in the presence of chemical potential. The results are plotted in the relevant...
Heavy-ion collisions quickly form a hot and dense phase of Quantum Chromodynamics (QCD) matter, so called the strongly interacting quark-gluon plasma (QGP). The QGP persists for only a much shorter time ($10^{-23}$s), then cools and translates into a lower temperature hadronic phase. Analyzing these final particles in a variety of different ways offers a unique insight into the properties of...
We report the first measurement of the rapidity-odd directed flow ($v_1$) of multi-strange baryons ($\Xi$ and $\Omega$) in Au+Au collisions as recorded by the STAR detector at the Relativistic Heavy Ion Collider.
We focus on particle species where all constituent quarks are produced, as opposed to possibly transported, and demonstrate using a novel analysis method that the coalescence sum...
We study the space-average electromagnetic (EM) fields weighted by the energy density in the central regions of heavy ion collisions. These average quantities can serve as a barometer for the magnetic-field induced effects such as the magnetic effect, the chiral separation effect and the chiral magnetic wave. Comparing with the magnetic fields at the geometric center of the collision, the...
Kyrill Bugaev$^{a, b}$, Oleksandr Vitiuk$^{c}$, Valery Pugatch$^{c}$, Vasyl Dobishuk$^{c}$, Sergiy Chernyshenko$^{c}$, Boris Grinyuk$^{b}$, Pavlo Panasiuk$^{a}$, Nazar Yakovenko$^{a}$, Elizaveta Zherebtsova$^{d}$, Larissa Bravina$^{e}$, Arkadiy Taranenko$^{d}$, Evgeny Zabrodin$^{e, f}$
and Marcus Bleicher$^{g}$
$^{a}$Department of Physics, Taras Shevchenko National University of Kyiv,...
Jets are produced in heavy-ion and nucleon-nucleon collisions from hard-scattered patrons of the incoming beams. We can infer the property of hot-dense QCD matter, known as Quark-Gluon Plasma (QGP), by studying the modified jet properties in heavy-ion collisions with respect to their vacuum reference. The STAR experiment has recently reported several novel jet measurements in heavy-ion...
Quarkonium states are good probes allowing to study the properties of quark-gluon plasma created in heavy ion-collisions. However, the production mechanism in p+p collisions is still an open question. It is often assumed that it factorizes into the hard scattering and non-perturbative hadronization. The basic quarkonium production models like Color Singlet, Color Octet and Color Evaporation...
We discuss the quantum fluctuations of energy in subsystems of hot relativistic gas for both scalar and spin half particles. For small subsystem sizes, we find a substantial increase of fluctuations compared to those known from standard thermodynamic considerations. However, if the size of the subsystem is sufficiently large, we reproduce the result for energy fluctuations in the canonical...
This report is devoted to the study of the influence of relativistic rotation on the confinement/deconfinement transition in SU(3) gluodynamics within lattice simulation. We perform the simulation in the reference frame which rotates with the system under investigation, where rotation is reduced to external gravitational field. To investigate the confinement/deconfinement transition the...
This presentation outlines ongoing activities on development of heavy ion accelerator facilities, providing high-brightness beams capable of generating intense beams of stable isotopes and radioactive ions. Manifested facilities goals is pushing the “intensity” and the “precision frontiers” to the extremes when accelerating full range of ion beam species from p+ to U to highest beam...
