Event-by-event mean p_T fluctuations in pp and Pb-Pb collisions measured by the ALICE experiment at the LHC

TL;DR

This paper investigates event-by-event fluctuations of mean transverse momentum in proton-proton and lead-lead collisions at the LHC, revealing scaling behaviors and deviations in central collisions, with comparisons to lower-energy data and simulations.

Contribution

It presents the first detailed measurement of mean p_T fluctuations across pp and Pb-Pb collisions at the LHC, highlighting scaling patterns and deviations in central heavy-ion collisions.

Findings

Little energy dependence in pp collisions.

Scaling behavior with multiplicity from pp to semi-central Pb-Pb.

Significant reduction of fluctuations in central Pb-Pb collisions.

Abstract

Non-statistical event-by-event fluctuations of the mean transverse momentum of charged particles in pp and Pb-Pb collisions are studied using the ALICE experiment at the LHC. Little collision energy dependence is observed in pp. The data indicate a common scaling behaviour with event multiplicity from pp to semi-central Pb-Pb collisions. In central Pb-Pb, the results deviate from this trend, exhibiting a significant reduction of the fluctuation strength. The results are compared with measurements in Au-Au collisions at lower energies and with Monte Carlo simulations.