Particle production at large p_(T) in Xe+Xe collisions with jet quenching using the higher twist approach

The production of π^(0),η,andφin the most central(0%-5%)Xe+Xe collisions at √s_(NN)=5.44 TeV is investigated in the framework of the perturbative QCD(pQCD)improved parton model at an accuracy of next-toleading order(NLO).The jet quenching effect is effectively incorporated by medium-modified fragmentation functions via the higher-twist approach.Predictions of the nuclear modification factors of π^(0),η,and φ as functions of the transverse momentum p_(T) are made with the jet transport parameter q_(0),which is extracted from the available experimental data of charged hadrons provided by ALICE and CMS.The particle ratios η/π^(0),φ/π^(0) as functions of p_(T) in Xe+Xe collisions at √s_(NN)=5.44 TeV as well as in 0%-5% Pb+Pb collisions at √s_(NN)=5.02 TeV are also presented.The numerical simulations of the scaled ratios of charged hadron production in the Xe+Xe 5.44 TeV system over those in the Pb+Pb 5.02 TeV system give a good description of the CMS data,and the scaled ratios of π^(0),η,and φ production coincide with the curve of charged hadron production.

A description of pseudorapidity distributions in p-p collisions at center-of-mass energy from 23.6 to 900 GeV

In the context of the combined model of evolution-dominated hydrodynamics ＋ leading particles, we discuss the pseudorapidity distributions of charged particles produced in p-p collisions. A comparison is made between the theoretical predictions and experimental measurements. The combined model works well in p-p collisions in the whole available energy region from √s=23.6 to 900 GeV.

A combined model for pseudorapidity distributions in p-p collisions at center-of-mass energies from 23.6 to 7000 GeV

In p-p collisions, the charged particles produced consist of two leading particles and those frozen out from the hot and dense matter created in the collisions. The two leading particles are in the projectile and target fragmentation regions, respectively, which, in this paper, are conventionally supposed to have Gaussian rapidity distributions. The hot and dense matter is assumed to expand according to unified hydrodynamics, a hydrodynamic model which unifies the features of the Landau and Hwa-Bjorken models, and freeze out into charged particles from a space-like hypersurface with a fixed proper time of TFo. The rapidity distribution of these charged particles can be derived analytically. The combined contribution from both leading particles and unified hydrodynamics is then compared against experimental data from a now available center-of-mass energy region from 23.6 to 7000 GeV. The model predictions are consistent with experimental measurements.