System size dependence of transverse momentum correlations at $\sqrt{s_{NN}}=$ 62.4 and 200 GeV at the BNL Relativistic Heavy Ion Collider

TL;DR

This study investigates how transverse momentum fluctuations and correlations vary with system size and collision energy in heavy-ion collisions, revealing independence from energy and system size and favoring transport models.

Contribution

It provides the first detailed comparison of $p_t$ correlations across different system sizes and energies, highlighting the role of transport processes over jetlike correlations.

Findings

$p_t$ correlations scaled by mean $p_t$ are energy and system size independent.

Transport models better match the experimental data than jet-based models.

Correlation results vary with collision centrality, $p_t$, $ heta$, and $ ext{azimuthal angle}$.

Abstract

We present a study of the average transverse momentum ($p_t$) fluctuations and $p_t$ correlations for charged particles produced in Cu+Cu collisions at midrapidity for $\sqrt{s_{NN}} =$ 62.4 and 200 GeV. These results are compared with those published for Au+Au collisions at the same energies, to explore the system size dependence. In addition to the collision energy and system size dependence, the $p_t$ correlation results have been studied as functions of the collision centralities, the ranges in $p_t$, the pseudorapidity $\eta$, and the azimuthal angle $\phi$. The square root of the measured $p_t$ correlations when scaled by mean $p_t$ is found to be independent of both colliding beam energy and system size studied. Transport-based model calculations are found to have a better quantitative agreement with the measurements compared to models which incorporate only jetlike correlations.