Work

Beam energy dependence of net-hyperon yield and its implication on baryon transport mechanism

Year: 2024

Type: article

Abstract: In the constituent quark model, each quark inside a baryon carries 1/3 unit of the baryon number. An alternative picture exists where the center of a Y-shaped topology of gluon fields, called the baryon junction, carries a unit baryon number. Studying baryon transport over a large rapidity gap ($δy$) in nuclear collisions provides a possible tool to distinguish these two pictures. A recent analysis of global data on net-proton yield at mid-rapidity in Au+Au collisions showed an exponential dependence on $δy$ and the exponential slope does not vary with event centrality, favoring the baryon junction picture. Since junctions are flavor blind, hyperons -- baryons containing valence strange quarks -- are expected to exhibit a similar behavior as the proton. This study aims to test this prediction by analyzing hyperon yields in Au+Au collisions at various energies. We observe that net-hyperon yields, after correcting for the strangeness production suppression, adhere to the expected exponential form. The extracted slope parameters for net-$Λ$, net-$Ξ$ and net-$Ω$ are consistent with each other and with those of net-proton within uncertainties, and exhibit no centrality dependence, further substantiating the baryon junction picture. Various implementations of the \texttt{PYTHIA} event generator, primarily based on valence quarks for baryon transport, are unable to simultaneously describe the slope parameters for all baryons.

Source: Physics Letters B

DOI: 10.1016/j.physletb.2024.139205

Authors: Chun Yuen Tsang, Rongrong Ma, Prithwish Tribedy, Zhangbu Xu

Institutions: Kent State University, Brookhaven National Laboratory

Language: English

Topic: High-Energy Particle Collisions Research

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: diamond

Funders: U.S. Department of Energy, Nuclear Physics