The study on the multiplicity dependence of ridge behavior in pp collisions at s=13 TeV at the LHC

Abstract

The long-range near-side ridge phenomenon in two-particle correlation is one of the key issues in studying the strong interaction. In particular, the hydrodynamic flow effect of the quark-gluon plasma (QGP) has explained it well for heavy-ion collisions, but is limited in its ability to explain the phenomenon in small systems. The Momentum Kick Model (MKM), on the other hand, suggests a fundamental explanation of the phenomenon through the kinematic process; the high-momentum jet particles collide with medium partons, transfer their momentum to them (called the “kick” process), and induce collective motion of the kicked-partons resulting in the ridge phenomenon. This MKM has successfully described the ridge structure in heavy-ion collisions at the RHIC. Furthermore, since the ridge phenomenon in small systems is prominent in high-multiplicity events, the MKM with multiplicity dependence (MKMwM) has been studied in pp collisions at the LHC using a relationship between the number of kicked-partons and the multiplicity through the impact parameter. In this research, we extend the previous study with more recent experimental data-driven parameters and apply them to the new measurements that have a wider multiplicity range with $p_T$ and ΔΦ bins at the LHC. We also predict the ridge structure at the energies scheduled by the LHC in the upcoming Run 3 experiments.