Forward-backward correlations between mean transverse momenta in Pb-Pb collisions with ALICE

TL;DR

This paper measures forward-backward correlations of mean transverse momentum in Pb-Pb collisions at LHC energies, providing insights into the initial state and medium evolution in heavy-ion collisions.

Contribution

It presents the first detailed measurement of event-by-event mean transverse momentum correlations in Pb-Pb collisions at two energies, demonstrating robustness against volume fluctuations.

Findings

FB correlations are sensitive to initial state properties.

Results are consistent with certain Monte Carlo models.

Correlation strength varies with collision centrality.

Abstract

Forward-backward (FB) correlations are considered to be a powerful tool for the exploration of the early dynamics of hadronic interactions. The FB correlation functions can be constructed from different observables calculated event-by-event in two separated pseudorapidity regions. We report measurements of event-by-event average transverse momentum correlations for charged particles in two separated pseudorapidity regions in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ and 5.02 TeV recorded with ALICE at the LHC. The event-by-event mean transverse momenta correlations are robust against volume fluctuations and thus the centrality determination methods, which provides higher sensitivity to the properties of the initial state and evolution of the medium created in A-A collisions. The strength of the FB correlation is calculated for different centralities of the Pb-Pb collisions. Results are compared with Monte Carlo event generators, such as HIJING and AMPT.