Transverse Momentum Fluctuations in Nuclear Collisions at 158 AGeV

TL;DR

This paper investigates event-by-event transverse momentum fluctuations in various nuclear collisions at 158 AGeV, revealing small dynamical fluctuations but notable system size dependence, especially in peripheral Pb+Pb interactions.

Contribution

It provides new measurements of transverse momentum fluctuations across different collision systems and compares them with theoretical model predictions.

Findings

Dynamical fluctuations are small across all systems.

Phi_pT shows a significant dependence on system size.

Largest Phi_pT observed in peripheral Pb+Pb collisions.

Abstract

Results are presented on event-by-event fluctuations in transverse momentum of charged particles, produced at forward rapidities in p+p, C+C, Si+Si and Pb+Pb collisions at 158 AGeV. Three different characteristics are discussed: the average transverse momentum of the event, the Phi_pT fluctuation measure and two-particle transverse momentum correlations. In the kinematic region explored, the dynamical fluctuations are found to be small. However, a significant system size dependence of Phi_pT is observed, with the largest value measured in peripheral Pb+Pb interactions. The data are compared with predictions of several models.