Transverse momentum fluctuation in ultra-central Pb+Pb collision at the LHC

2023/12/15 by Rupam Samanta, S. Bhatta, Samanta, Rupam +7
Physics and Astronomy · #FOS: Physical sciences #High-Energy Particle Collisions Research #Nuclear Experiment (nucl-ex) #Nuclear Theory (nucl-th) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions

paper · pdf · doi:10.48550/arxiv.2312.10161

openalex publication_date 2023/12/15 · openalex created_date 2023/12/20 · openalex updated_date 2026/07/28

Abstract

The ATLAS collaboration has recently observed that the variance of the transverse momentum per particle ([ p_t ]), when measured as a function of the collision multiplicity (N_ch) in Pb+Pb collisions, decreases by a factor 2 for the largest values of N_ch, corresponding to ultra-central collisions. We show that this phenomenon is naturally explained by invoking impact parameter (b) fluctuations, which contribute to the variance, and gradually disappear in ultra-central collisions. It implies that N_ch and [ p_t ] are strongly correlated at fixed b, which is explained by the local thermalization of the QGP medium.

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