Characterizing system dynamics with two-particle transverse momentum correlations in pp collisions at $\sqrt{s} = 7\;\text{TeV}$ and p$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02\;\text{TeV}$

TL;DR

This study measures two-particle transverse momentum correlations in small collision systems to investigate possible viscous effects and compare with larger Pb-Pb collisions, providing insights into particle production and medium properties.

Contribution

It presents the first measurements of the $G_2$ correlator in pp and p-Pb collisions at LHC energies, exploring viscous effects in smaller systems and comparing results with Monte Carlo models.

Findings

Correlator shape varies with multiplicity, indicating possible viscous effects.

Comparison with models shows some discrepancies, suggesting new physics or model improvements.

Evidence of longitudinal broadening in correlations as multiplicity increases.

Abstract

The two-particle differential transverse momentum correlator $G_{2}$ recently measured in Pb$-$Pb collisions, emerged as a powerful tool to gain insight into particle production mechanisms and to infer transport properties such as the ratio of shear viscosity to entropy density of the medium created in Pb$-$Pb collisions. In this poster, recent ALICE measurements of this correlator in pp collisions at $\sqrt{s}=7$ and p$-$Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV are presented to search, in particular, for viscous effects expected to arise in fluid-like systems produced in these collisions. The strength and shape of the correlator are studied as a function of produced particle multiplicity to look for longitudinal broadening that might reveal the presence of viscous effects in these smaller systems. The measured correlators and their evolution from pp and p$-$Pb to Pb$-$Pb are additionally compared to predictions from Monte Carlo models, and the potential presence of viscous effects is discussed.