scholarly journals Energy density and path-length dependence of the fractional momentum loss in heavy-ion collisions at sNN from 62.4 to 5020 GeV

2018 ◽  
Vol 97 (1) ◽  
Author(s):  
Antonio Ortiz ◽  
Omar Vázquez
Author(s):  
Aditya Nath Mishra ◽  
Guy Paić ◽  
C. Pajares ◽  
R. P. Scharenberg ◽  
B. K. Srivastava

In this paper, we analyzed charged particle transverse momentum spectra in high multiplicity events in proton–proton and nucleus–nucleus collisions at LHC energies from the ALICE experiment using the color string percolation model (CSPM). The color reduction factor and associated string density parameters are extracted for various multiplicity classes in [Formula: see text] collisions and centrality classes for heavy-ion collisions at various LHC energies to study the effect of collision geometry and collision energy. These parameters are used to extract the thermodynamical quantities temperature and the energy density of the hot nuclear matter. A universal scaling is observed in initial temperature when studied as a function of charged particle multiplicity scaled by transverse overlap area. From the measured initial energy density [Formula: see text] and the initial temperature T, a dimensionless quantity [Formula: see text] is constructed which is used to obtain the degrees of freedom (DOF) of the deconfined phase. A two-step behavior and a sudden increase in DOF of [Formula: see text]47 for the ideal gas, above the hadronization temperature (T [Formula: see text] 210[Formula: see text]MeV), are observed in case of heavy-ion collisions at LHC energies.


1993 ◽  
Vol 08 (14) ◽  
pp. 1291-1296 ◽  
Author(s):  
A. DUMITRU ◽  
D. H. RISCHKE ◽  
H. STÖCKER ◽  
W. GREINER

We study photon production from quark-gluon plasmas with different baryo-chemical potentials µ B but fixed, given energy density ε. We find that the rate to lowest order O(ααs) decreases strongly with increasing µ B . Since to our knowledge µ B can be large in heavy-ion collisions, this result may be of importance concerning photon production as a signature for the creation of a quark-gluon plasma.


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