Sandeep Chatterjee

Freeze-Out Parameters in Heavy-Ion Collisions at AGS, SPS, RHIC, and LHC Energies

We review the chemical and kinetic freeze-out conditions in high energy heavy-ion collisions for AGS, SPS, RHIC, and LHC energies. Chemical freeze-out parameters are obtained using produced particle yields in central collisions while the corresponding kinetic freeze-out parameters are obtained using transverse momentum distributions of produced particles. For chemical freeze-out, different freeze-out scenarios are discussed such as single and double/flavor dependent freeze-out surfaces. Kinetic freeze-out parameters are obtained by doing hydrodynamic inspired blast wave fit to the transverse momentum distributions. The beam energy and centrality dependence of transverse energy per charged particle multiplicity are studied to address the constant energy per particle freeze-out criteria in heavy-ion collisions.

Stabilizing hadron resonance gas models

We examine the stability of hadron resonance gas models by extending them to include undiscovered resonances through the Hagedorn formula. We find that the influence of unknown resonances on thermodynamics is large but bounded. We model the decays of resonances and investigate the ratios of particle yields in heavy-ion collisions. We find that observables such as hydrodynamics and hadron yield ratios change little upon extending the model. As a result, heavy-ion collisions at the RHIC and LHC are insensitive to a possible exponential rise in the hadronic density of states, thus increasing the stability of the predictions of hadron resonance gas models in this context. Hadron resonance gases are internally consistent up to a temperature higher than the crossover temperature in QCD, but by examining quark number susceptibilities we find that their region of applicability ends below the QCD crossover.

Production of Light Nuclei in Heavy Ion Collisions Within Multiple Freezeout Scenario

We discuss the production of light nuclei in heavy ion collisions within a multiple freezeout scenario. Thermal parameters extracted from the fits to the observed hadron yields are used to predict the multiplicities of light nuclei. Ratios of strange to non strange nuclei are found to be most sensitive to the details of the chemical freezeout. The well known disagreement between data of

Directed flow of charm quarks as a witness of the initial strong magnetic field in ultra-relativistic heavy ion collisions

^3_\Lambda\text{H/}^3\text{He}

Separation of flow from the chiral magnetic effect in U+U collisions using spectator asymmetry

and

Freezeout hypersurface at energies available at the CERN Large Hadron Collider from particle spectra: Flavor and centrality dependence

\overline{^3_\Lambda\text{H/}^3\text{He}}

Including the fermion vacuum fluctuations in the (2+1) flavor Polyakov quark-meson model

at

Contrasting Freezeouts in Large Versus Small Systems

\sqrt{s_{NN}}=200

Bulk viscosity for pion and nucleon thermal fluctuation in the hadron resonance gas model

GeV and models based on thermal as well as simple coalescence using a single chemical freezeout surface goes away when we let the strange and non strange hadrons freezeout at separate surfaces. At the LHC energy of

Freezeout systematics due to the hadron spectrum

\sqrt{s_{NN}}=2700