Participant-like scaling behavior of multiplicity and charged hadron spectra in relativistic heavy ion collisions

TL;DR

This paper introduces a Glauber-inspired model to parameterize charged particle multiplicity and spectra in heavy ion collisions, explaining suppression patterns and surface emission effects without requiring high-pT suppression.

Contribution

The model uniquely accounts for multiplicity and spectra using sub-components of nucleons, reproducing data without high-pT suppression and unifying observations across collision energies.

Findings

Reproduces multiplicity and spectra with fixed sub-component yields.

Suppression confined to low- and intermediate-pT, absent at high-pT.

Suppression patterns are consistent across 200GeV and 62.4GeV collisions.

Abstract

We present a method for parameterizing the charged particle multiplicity and charged hadron spectra from heavy ion data with a simple, Glauber-inspired, model. The basis of this model is derived from the observation of leading hadrons in $pp$ collisions and the number of interactions calculated by a Glauber model. Singly hit and multiply hit nucleons are treated as different sub-components of the same collision. With this scheme, for fixed sub-component yields, we find that the multiplicity and charged hadron spectra can be reproduced, without the need for large suppression at high-p$_T$. Suppression is still observed, in the low- to intermediate-p$_T$ region, but this is confined to suppression of surface emission partons. At high-p$_T$, the suppression disappears entirely, leaving only a possible Cronin-type enhancement. The suppression observed in 200GeV collisions is found to be the same for 62.4GeV data.