Baryon Stopping in Au+Au and p+p collisions at 62 and 200 GeV

TL;DR

This paper reports measurements of proton and antiproton distributions in p+p and Au+Au collisions at 62 and 200 GeV, providing insights into baryon stopping and transport properties in high-energy nuclear collisions.

Contribution

It presents new rapidity density measurements of protons and antiprotons, analyzing net-proton yields to understand baryon stopping in different collision systems and centralities.

Findings

Similar net-proton rapidity dependence in p+p and peripheral Au+Au collisions.

Distinct net-proton rapidity dependence in central Au+Au collisions.

Net-baryon yields inform on rapidity loss and baryon transport.

Abstract

BRAHMS has measured rapidity density distributions of protons and antiprotons in both p+p and Au+Au collisions at 62 GeV and 200 GeV. From these distributions the yields of so-called "net-protons", that is the difference between the proton and antiproton yields, can be determined. The rapidity dependence of the net-proton yields from peripheral Au+Au collisions is found to have a similar behaviour to that found for the p+p results, while a quite different rapidity dependence is found for central Au+Au collisions. The net-proton distributions can be used together with model calculations to find the net-baryon yields as a function of rapidity, thus yielding information on the average rapidity loss of beam particles, the baryon transport properties of the medium, and the amount of "stopping" in these collisions.