Dependence of net-hyperon production at mid-rapidity on beam energy and its implication on baryon number carrier

¹ Brookhaven National Laboratory, Upton, NY, USA
² Kent State University, 800 E Summit St, Kent, OH, USA

Published online: 27 January 2025

Abstract

The conventional picture of baryon number is that each valence quark inside a baryon carries 1/3 unit of baryon number. However, an alternative picture exists where the center of a Y-shaped topology of gluon fields, called the baryon junction, carries 1 unit of baryon number. Previous analysis suggests that the nature of the baryon number carrier is sensitive to net-proton yields at mid-rapidity in heavy-ion collisions, and experimental measurements potentially challenge the conventional picture. In this study, we analyzed published data from the BES-I program at RHIC, which performed Au+Au collisions at center-of-mass energies ranging from 7.7 to 200 GeV. We investigated the rapidity dependence of net-hyperon yields after correcting for strangeness production suppression, and found that the net-hyperon yields at mid-rapidity follow an exponential dependence on the beam rapidity. This behavior is consistent with Regge model predictions. Moreover, the exponential slopes for net- Λ, net-Ξ, and net-Ω are consistent with each other, suggesting that the baryon transport is flavor blind. Conventional models like PYTHIA, which use valence quarks as the baryon number carrier, have difficulty reproducing this transport behavior.