Baryon-antibaryon production asymmetry in relativistic heavy ion collisions

TL;DR

This paper explains the observed universal correlation between baryon and meson yield ratios in relativistic heavy ion collisions using a quark combination model, providing a theoretical basis for experimental data.

Contribution

It introduces a quark combination framework to analyze baryon-antibaryon asymmetry and explains yield ratios across different energies and rapidities.

Findings

Successfully explains $ar{p}/p$ and $K^{-}/K^{+}$ ratios at various energies.

Predicts the universality of hadron production in heavy ion collisions.

Suggests further experimental tests at RHIC energies.

Abstract

Experimental data at RHIC and SPS energies suggest a systematic correlation between yield ratio $\bar{p}/p$ and $K^{-}/K^{+}$, which reveal some universality of hadron production in relativistic heavy ion collisions. We propose an explanation based on the quark combination mechanism in which the production asymmetry between baryons and antibaryons is focused on especially. We start from the basic ideas of quark combination to carry out a general analysis of the properties of the global production of baryons and mesons and obtain the yields of baryons, antibaryons and mesons as functions of the number of constituent quarks and antiquarks just before hadronization. In particular, we study effects of quark-antiquark asymmetry on the ratio of (anti-)baryons to mesons and that of antibaryons to baryons. We use these formula to well explain the data of $\bar{p}/p$ and $K^{-}/K^{+}$ at different of collision energies and rapidities and suggest further measurements at moderate RHIC energies in the mid-forward rapidity regions to make the decisive test of this universality.