Effect of color reconnection on multiplicity dependent charged particle production in Pythia-generated $pp$ collisions at the LHC energies

TL;DR

This study investigates how color reconnection influences the multiplicity dependence of charged particle production in proton-proton collisions at LHC energies using PYTHIA simulations, revealing significant effects on transverse momentum spectra and effective temperature.

Contribution

It demonstrates the impact of color reconnection on multiplicity-dependent particle production, challenging the notion that phase transition is the sole cause of observed effects.

Findings

Charged particle spectra become harder with higher multiplicity.

Effective temperature and average transverse momentum increase then decrease with multiplicity.

Color reconnection significantly flattens these dependencies.

Abstract

The transverse momentum ($p_{\rm T}$) spectra of inclusive charged particles and its dependence on charged-particle multiplicity are studied in pp collisions at $\sqrt{s}$ = 7 and 13 TeV using the Monte Carlo event generator PYTHIA Monash. The results of the minimum bias pp collisions are compared with the ALICE published results at the same energies. The variations of the effective temperature (T$_{\rm {Eff}}$) and average transverse momentum ($\langle p_{\mathrm{T}} \rangle$) with charged-particle multiplicity are also studied. The $p_{\rm T}$ spectra of the charged particles are observed to get harder with increasing charged-particle multiplicity. Moreover, a sharp increase in the T$_{\rm {Eff}}$ and $\langle p_{\mathrm{T}} \rangle$ with increasing multiplicity followed by a gradual decrease with the further increase in multiplicity could also be observed. Further, it could be observed that the color reconnection (CR) mechanism has a considerable effect on flattening the T$_{\rm {Eff}}$ and $\langle p_{\mathrm{T}} \rangle$ with increasing multiplicity, which indicates that phase-transition may not necessarily be the only mechanism that could give rise to such an effect.