Determination of classes of events in multiplicity and its relevance to centrality in high energy Pb-Pb and p-Pb collisions in different MC models

Abstract

We present the critical review of estimates of centrality in nucleus-nucleus and proton-nucleus collision. We construct a consequential method of centrality determination in terms of the multiplicity and the impact parameter. Using Monte-Carlo simulations we analyze the consistency of the concept of centrality in the cases of nucleus-nucleus and proton-nucleus collisions for heavy and light ions. We discuss the results of this analysis and consider a universal procedure to obtain certain centrality classes, where the fluctuations related to event-by-event variance in the impact parameter and/or the number of nucleons-participants are minimized.

Global analysis of nuclear parton distribution functions and their uncertainties at next-to-next-to-leading order

“…Since the first indications that the DIS structure functions measured in the charged-lepton scattering of the nuclei, (ℓ ± + nucleus), differ significantly from those measured in the isolated nucleons, there has been also a continuous interest in fully understanding the microscopic mechanism responsible in the nuclei. The importance of nuclear effects in parton distribution functions is due to the interpretation of any hard-process results involving nuclei in p+A [45], d+A [46] and A+A [47,48] collisions, such as heavy ions collisions at the present BNL-RHIC [49,50] and CERN-LHC [51] colliders and also future proposed electronnucleon colliders such as EIC, eRHIC or the LHeC [52][53][54][55][56][57]. These DIS data play an important role for the observed nuclear modifications.…”