Regular Article - Theoretical Physics
Effects of shadowing in Pb + Pb collisions at energies available at the CERN Large Hadron Collider within the HIJING code
Physics Department, Faculty of Applied Science, Umm Al-Qura University, P.O. Box (10471), 21955, Makkah, Saudi Arabia
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Accepted: 17 August 2018
Published online: 21 September 2018
The charged particle central rapidity density per participant nucleon pair () as a function of the average number of participants () for () collisions at and 200 GeV, and collisions at and 5.02 TeV is investigated within an improved HIJING (ImHIJING/Cas) model. Compared to the standard HIJING version, it incorporates: i) more consistent parton densities, ii) a QCD running coupling, defined by the exact solution of the renormalization group equation, and iii) a spatial dependent nucleon shadowing, triggered by collective nucleon interactions with an incoming nucleon, and simulated by the collective cascade recipe. Predictions are compared using four different settings of nuclear shadowing of partons, based on the standard HIJING1.0(2.0) parameterizations. It is shown that ImHIJING/Cas/Set2 (that with both quark and soft gluon shadowing of strength can nicely reproduce the measured centrality dependence of at RHIC energy. As for LHC, a reduction of by % at very peripheral (90-100%) collisions, as compared to free nucleon-nucleon collisions, is found to reproduce the measured data. The values of used in ImHIJING/Cas/Set2 calculations for most central 0-3(5)% collisions at RHIC(LHC) energy, are found to be consistent with those employed in Set2 that reproduce the measured structure function ratios () as a function of x.
© SIF, Springer-Verlag GmbH Germany, part of Springer Nature, 2018