scholarly journals Skewness of mean transverse momentum fluctuations in heavy-ion collisions

2021 ◽  
Vol 103 (2) ◽  
Author(s):  
Giuliano Giacalone ◽  
Fernando G. Gardim ◽  
Jacquelyn Noronha-Hostler ◽  
Jean-Yves Ollitrault
2018 ◽  
Vol 171 ◽  
pp. 18015
Author(s):  
Xinjie Huang

In these proceedings, we present the latest measurements of J/ψ and ϒ by the STAR experiment. The J/ψ and ϒ production measured in p+p collisions provide new baselines for similar measurements in Au+Au collisions, while the measurements in p+Au collisions can help quantify the cold nuclear matter effects. The J/ψ υ2 is measured in both U+U and Au+Au collisions to place constraints on the amount of J/ψ arising from recombination of deconfined charm and anti-charm pairs. Furthermore, the nuclear modification factors for ground and excited ϒ states as a function of transverse momentum and centrality are presented, and compared to those measured at the LHC as well as to theoretical calculations.


2020 ◽  
Vol 29 (08) ◽  
pp. 2050057
Author(s):  
De-Xian Wei

Based on A Multi-Phase Transport (AMPT) model simulations, the transverse momentum dependent decorrelation has been studied in Pb–Pb collisions at [Formula: see text] and 5.02 TeV, respectively. It has been found that the mix-order factorization ratio [Formula: see text] value deviates significantly from unity in noncentral collisions. Such effect becomes stronger with an increase in the [Formula: see text] difference [Formula: see text]. These decorrelations are not only between the same order harmonic but also between the different order harmonic, which as a result of the initial fluctuations appear between the different phase spaces. It has also been found that the correlations involving higher powers of the flow vector yield stronger decorrelation, [Formula: see text], except for the weighted factorization ratio [Formula: see text]. The breaking phenomenon of these factorization ratios indicated that it provides a possible observation for studying the initial fluctuation properties of heavy-ion collisions.


2007 ◽  
Vol 16 (07n08) ◽  
pp. 1930-1936 ◽  
Author(s):  
WEI LIU ◽  
CHE MING KO ◽  
BEN-WEI ZHANG

A gluon or quark jet traversing through a quark-gluon plasma can be converted into a quark or gluon jet through scatterings with thermal partons. Their conversion rates due to two-body elastic and inelastic scattering as well as scatterings involving gluon radiation are evaluated in the lowest order in Quantum Chromodynamics (QCD). Including both energy loss and conversions of quark and gluon jets in the expanding quark-gluon plasma produced in relativistic heavy ion collisions, we find a net conversion of quark jets to gluon jets. This reduces the difference between the nuclear modification factors for quark and gluon jets in central heavy ion collisions and thus enhances the p/π+ and [Formula: see text] ratios at high transverse momentum. Using the larger QCD coupling constant from lattice QCD calculations than that given by the perturbative QCD further enhances the net quark to gluon jet conversion rate, leading to a closer similarity between these ratios at high transverse momentum in central Au + Au collisions at [Formula: see text] and in p + p collisions at same energy as observed in experiments.


2019 ◽  
Vol 790 ◽  
pp. 339-344 ◽  
Author(s):  
Mariola Kłusek-Gawenda ◽  
Ralf Rapp ◽  
Wolfgang Schäfer ◽  
Antoni Szczurek

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.


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