A transport model study of multiparticle cumulants in p + p collisions at 13 TeV

Abstract

Flow-like signals including the ridge structure observed in small collision systems that are similar to those in large collision systems have led to questions about the onset of collectivity in nuclear collisions. In this study, we use the string melting version of a multi-phase transport model with or without the sub-nucleon geometry for the proton to study multiparticle cumulants in p+p collisions at 13 TeV. Both versions of the model can produce negative c2{4} values at high multiplicities. In addition, the dependences of c2{4} and c2{2} on the parton cross section σ are found to be strong and non-monotonous, where only an intermediate range of σ values leads to negative c2{4}. Furthermore, the model with sub-nucleon geometry better describes the multiplicity dependence of c2{4}, demonstrating the importance of the sub-nucleon geometry for studies of small systems.