Transverse Energy Measurements from the Beam Energy Scan in PHENIX

TL;DR

This study measures transverse energy distributions across various collision systems and energies at RHIC, revealing power-law behavior and scaling with constituent quark participants, advancing understanding of energy density in heavy-ion collisions.

Contribution

It provides comprehensive transverse energy measurements over a wide energy range and demonstrates that constituent quark scaling better describes centrality dependence.

Findings

Midrapidity Bjorken energy density follows a power law from 7.7 GeV to 2.76 TeV.

Data are independent of collision system size at fixed energy.

Constituent quark participant scaling outperforms nucleon participant scaling.

Abstract

Transverse energy distributions at midrapidity have been measured by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) for Au+Au, U+U, Cu+Au, Cu+Cu, He+Au, d+Au, and p+p collisions over a wide energy range from $\sqrt{s_{NN}}$ = 7.7 GeV to $\sqrt{s_{NN}}$ = 200 GeV as a function of centrality. For central Au+Au collisions, it is observed that the midrapidity Bjorken energy density demonstrates a power law behavior from $\sqrt{s_{NN}}$ = 7.7 GeV to $\sqrt{s_{NN}}$ = 2.76 TeV. At a given collision energy, the data presented as a function of $N_{part}$ are independent of the size of the collision system. For Au+Au, Cu+Au, and Cu+Cu collisions, the centrality-dependent data are better described by scaling with the number of constituent quark participants than scaling with the number of nucleon participants.