We model the hot and dense strongly interacting mater produced in high energy heavy ion collisions using relativistic hydrodynamics. Several different sources of real photons produced during these collisions are considered and their relative importance is assessed. We include contributions from QCD jets, which are allowed to loose and gain energy as they proceed through the hot matter. This is treated within the AMY formalism. We obtain photon spectra, R_{AA}, and v_2 in agreement with measurements performed by the PHENIX collaboration.
We present a fully three-dimensional initial state model for relativistic heavy-ion collisions at RHIC Beam Energy Scan (BES) collision energies. The initial energy and net baryon density profiles are produced based on a classical string deceleration model. The baryon stopping and fluctuations during this early stage of the collision are investigated by studying the net baryon rapidity distribution and longitudinal decorrelation of the transverse geometry.
STAR collaboration at RHIC has recently measured the polarization of $Λ$ hyperons in non-central heavy ion collisions in the RHIC Beam Energy Scan (BES) program. The magnitude of the polarization was found to decrease from few percents at the lowest BES energies to $\approx0.2$% at the top RHIC energy. The polarization signal has been reproduced in different hydrodynamic calculations assuming a thermodynamic spin-vorticity coupling mechanism at the Cooper-Frye hypersurface. In this work an extension of our existing calculations of the $Λ$ polarization in the RHIC BES program to the top RHIC an…
Using a hybrid (viscous hydrodynamics + hadronic cascade) framework, we model the bulk dynamical evolution of relativistic heavy-ion collisions at Relativistic Heavy Ion Collider (RHIC) Beam Energy Scan (BES) collision energies, including the effects from non-zero net baryon current and its dissipative diffusion. This framework is in full (3+1)D, which allows us to study the non-trivial longitudinal structure and dynamics of the collision systems, for example baryon stopping and transport, as well as longitudinal fluctuations. For the first time, the quantitative effect of net-baryon diffusion…
Thermal nature of charmonium transverse momentum spectra from Au-Au collisions at the highest energies available at the BNL Relativistic Heavy Ion Collider (RHIC)
In hydrodynamic approach to relativistic heavy ion collisions, hadrons with nonzero spin, produced out of the hydrodynamic medium, can acquire polarization via spin-vorticity thermodynamic coupling mechanism. The hydrodynamical quantity steering the polarization is the thermal vorticity, that is minus the antisymmetric part of the gradient of four-temperature field. Based on this mechanism there have been several calculations in hydrodynamic and non-hydrodynamic models for non-central heavy ion collisions in the RHIC Beam Energy Scan energy range, showing that the amount of polarization of pro…
Recent measurements of the centrality and rapidity dependence of single inclusive jet production in p+Pb collisions at the LHC have revealed large and non-trivial nuclear modification of the production cross section for this process. In this paper, we explore to what extent such nuclear modification can be understood by the framework of standard cold nuclear matter effects, in particular initial-state cold nuclear matter energy loss. We demonstrate quantitatively that theoretical calculations which include medium-induced radiative corrections can describe rather reasonably the attenuation of t…
We study the radiative correction to $p_\perp$-broadening of a fast quark in a quark-gluon plasma beyond the soft gluon approximation. We find that the radiative contribution to quark $\langle p_\perp^2\rangle$ for RHIC and LHC conditions is negative.
The Linear Boltzmann Transport (LBT) model coupled to hydrodynamical background is extended to include transport of both light partons and heavy quarks through the quark-gluon plasma (QGP) in high-energy heavy-ion collisions. The LBT model includes both elastic and inelastic medium-interaction of both primary jet shower partons and thermal recoil partons within perturbative QCD (pQCD). It is shown to simultaneously describe the experimental data on heavy and light flavor hadron suppression in high-energy heavy-ion collisions for different centralities at RHIC and LHC energies. More detailed in…
The properties of strange pseudoscalar and vectors mesons as well as strange baryon resonances in dense matter are reviewed. Some open questions on the properties of strange hadrons in medium are addressed, such as the experimental signatures of in-medium effects coming from the hadronic phase on the final observables in heavy-ion collisions for the experimental conditions at SIS, RHIC and LHC energies.
v4 from ideal and viscous hydrodynamic simulations of nuclear collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC)
Based on the data-driven analysis, the mid-rapidity transverse momentum spectra of charged hadrons produced in central and peripheral gold-gold (Au-Au) collisions from the Beam Energy Scan (BES) program at the relativistic Heavy Ion Collider (RHIC) are fitted by the blast-wave model with Boltzmann-Gibbs statistics. The model result are in agreement with the experimental data measured by the STAR Collaboration at the RHIC-BES energies. We observe that the kinetic freeze-out temperature, transverse flow velocity, mean transverse momentum, and initial temperature increase with the collision energ…
We take the experimental data for transverse momentum spectra of identified charged hadrons in different centrality classes for nucleus-nucleus (A+A) collisions at various Relativistic Heavy-Ion Collider (RHIC) energies measured by the STAR collaboration. We analyse these data in the framework of color string percolation model (CSPM) in order to extract various percolation parameters at different centralities at RHIC energies to study the effect of collision geometry and collision energy. We use these parameters to study the centrality dependent behaviour of initial temperature of the percolat…
Particle production in relativistic $pp$($\overline{p}$) and $AA$ collisions at RHIC and LHC energies with Tsallis statistics using the two-cylindrical multisource thermal model
The centrality dependence of the charged-particle multiplicity densities ($dN_{ch}/dη$) and transverse energy densities ($dE_{T}/dη$) are investigated using the two-component Glauber approach for broad range of energies in heavy ion collisions at RHIC and LHC. A comprehensive study shows that the data is well described within the framework of two component model which includes the contribution of "soft processes" and "hard processes" for different centrality classes and energies. The data at two different energies are compared by means of the ratio of $dN_{ch}/dη$ (and $dE_{T}/dη$) to see the …
The experimental data from the RHIC and LHC experiments of invariant pT spectra in A+A and p + p collisions are analysed with Tsallis distributions in different approaches. The information about the freeze-out surface in terms of freeze-out volume, temperature, chemical potential and radial flow velocity for different particle species are obtained. Further, these parameters are studied as a function of the mass of the secondary particles. A mass-dependent differential freeze-out is observed which does not seem to distinguish between particles and their antiparticles. Further a mass-hierarchy i…
A parameter-free calculation for J/Psi suppression in pA collisions, based on the dipole description, is confronted with the new data from the PHENIX experiment. Achieving good agreement, we employed this model predicting the contribution of initial state interactions (ISI) to J/Psi suppression in AA collisions. Such a transition from pA to AA is not straightforward, since involves specific effects of double color filtering and boosting of the saturation scale. Relying on this refined ISI contribution, we updated the previous analysis of RHIC data on J/Psi production in Cu-Cu and Au-Au collisi…
We investigate consequences of local energy-momentum conservation for initial eccentricity coefficients in heavy ion collisions at not too high energies relevant for CERN SPS and RHIC BES. Different models of energy density available for pion production are considered. We study dependence of eccentricity coefficients on space-time rapidity for different impact parameters. The naive formula how to define eccentricities breaks with our initial conditions and must be corrected. We predict considerable eccentricities for $ε_{1,2,3,4}$ and specific dependence on space-time rapidity as well as on im…
