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

2015 ◽  
Vol 2015 ◽  
pp. 1-20 ◽  
Author(s):  
Sandeep Chatterjee ◽  
Sabita Das ◽  
Lokesh Kumar ◽  
D. Mishra ◽  
Bedangadas Mohanty ◽  
...  

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.

2007 ◽  
Vol 16 (07n08) ◽  
pp. 1883-1889 ◽  
Author(s):  
◽  
DEBASISH DAS

The influence of Bose–Einstein statistics on multi-particle production characterized for various systems and energies by the STAR collaboration provides interesting information about the space-time dynamics of relativistic heavy-ion collisions at RHIC. We present the centrality and transverse mass dependence measurements of the two-pion interferometry in Au + Au collisions at [Formula: see text] and Cu + Cu collisions at [Formula: see text] and 200 GeV. We compare the new data with previous STAR measurements from p + p , d + Au and Au + Au collisions at [Formula: see text]. In all systems and centralities, HBT radii decrease with transverse mass in a similar manner, which is qualitatively consistent with collective flow. The scaling of the apparent freeze-out volume with the number of participants and charged particle multiplicity is studied. Measurements of Au + Au collisions at same centralities and different energies yield different freeze-out volumes, which mean that N part is not a suitable scaling variable. The multiplicity scaling of the measured HBT radii is found to be independent of colliding system and collision energy.


2021 ◽  
Vol 136 (6) ◽  
Author(s):  
Rajendra Nath Patra ◽  
Bedangadas Mohanty ◽  
Tapan K. Nayak

AbstractThe thermodynamic properties of matter created in high-energy heavy-ion collisions have been studied in the framework of the non-extensive Tsallis statistics. The transverse momentum ($$p_\mathrm{T}$$ p T ) spectra of identified charged particles (pions, kaons, protons) and all charged particles from the available experimental data of Au-Au collisions at the Relativistic Heavy Ion Collider (RHIC) energies and Pb-Pb collisions at the Large Hadron Collider (LHC) energies are fitted by the Tsallis distribution. The fit parameters, q and T, measure the degree of deviation from an equilibrium state and the effective temperature of the thermalized system, respectively. The $$p_\mathrm{T}$$ p T  spectra are well described by the Tsallis distribution function from peripheral to central collisions for the wide range of collision energies, from $$\sqrt{s_\mathrm{NN}}$$ s NN = 7.7 GeV to 5.02 TeV. The extracted Tsallis parameters are found to be dependent on the particle species, collision energy, centrality, and fitting ranges in $$p_\mathrm{T}$$ p T . For central collisions, both q and T depend strongly on the fit ranges in $$p_\mathrm{T}$$ p T . For most of the collision energies, q remains almost constant as a function of centrality, whereas T increases from peripheral to central collisions. For a given centrality, q systematically increases as a function of collision energy, whereas T has a decreasing trend. A profile plot of q and T with respect to collision energy and centrality shows an anti-correlation between the two parameters.


2020 ◽  
Vol 101 (5) ◽  
Author(s):  
P. Alba ◽  
V. Mantovani Sarti ◽  
J. Noronha-Hostler ◽  
P. Parotto ◽  
I. Portillo-Vazquez ◽  
...  

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