Transverse momentum fluctuations as a probe of thermalization and collective dynamics of QGP

TL;DR

This paper investigates transverse momentum fluctuations in ultrarelativistic heavy-ion collisions, demonstrating their connection to QGP thermalization and collective behavior, and introduces a differential fluctuation measure called $v_0(p_T)$.

Contribution

It introduces the $v_0(p_T)$ measure to probe collective dynamics and thermalization of QGP, linking fluctuations to flow phenomena.

Findings

Steep decline in transverse momentum fluctuation variance in ultracentral Pb+Pb collisions.

$v_0(p_T)$ acts as a probe of collective behavior similar to anisotropic flow.

Fluctuations are connected to the thermalization process of the QGP.

Abstract

We study fluctuations of mean transverse momentum per particle ($[p_T]$) in ultrarelativistic heavy-ion collisions. We show that the steep fall in the variance of transverse momentum fluctuation in ultracentral Pb+Pb collision serves as a natural consequence of the thermalization of the QGP medium. We study the correlation between the spectra and $[p_T]$ which maps these fluctuations differentially and dubbed as $v_0(p_T)$. We highlight the importance of $v_0(p_T)$ showing that it plays similar role as anisotropic flow when probing the collective nature of QGP.