Can Baryon Stopping Be Understood within a Hadronic Transport Approach

Justin Mohs,Sangwook Ryu,Hannah Elfner

doi:10.3390/proceedings2019010002

Abstract

The changing shape of the rapidity spectrum of net protons over the SPS energy range is still lacking theoretical understanding. In this work, a model for string excitation and string fragmentation is implemented for the description of high energy collisions within a hadronic transport approach. The free parameters of the string model are tuned to reproduce the experimentally measured particle production in proton-proton collisions. With the fixed parameters we advance to calculations for heavy ion collisions, where the shape of the proton rapidity spectrum changes from a single peak to a double peak structure with increasing beam energy in the experiment. We present calculations of proton rapidity spectra at different SPS energies in heavy ion collisions. Qualitatively, a good agreement with the experimental findings is obtained. In a future work, the formation process of string fragments will be studied in detail aiming to quantitatively reproduce the measurement.

Highlights

Heavy ion collisions provide the opportunity of probing strongly interacting matter under hot √and dense conditions
With the fixed parameters we advance to calculations for heavy ion collisions, where the shape of the proton rapidity spectrum changes from a single peak to a double peak structure with increasing beam energy in the experiment
We present calculations of proton rapidity spectra at different SPS energies in heavy ion collisions

Summary

Introduction

Heavy ion collisions provide the opportunity of probing strongly interacting matter under hot. In lead-lead collisions in this energy range, a region in the phase diagram of strongly interacting matter with large baryon chemical potential can be studied. The stopping of baryons is of major interest, since the net-baryon density determines the baryon chemical potential within heavy ion collisions. While P YTHIA [5] is employed directly for treating hadronic interactions at high energies, another calculation is necessary in the lower energy region, where perturbative methods are not applicable. Comparing to experimental results for heavy ion collisions is only meaningful, if the interactions between nucleons are understood.

Proton-Proton Collisions

Heavy Ion Collisions