Universal Formula for Baryon Spectra in Heavy-ion Collisions and its Implications

TL;DR

This paper uncovers a universal formula describing baryon transverse momentum spectra in heavy-ion collisions across various energies and baryon types, challenging conventional fluid flow models and revealing quark distribution features.

Contribution

It introduces a universal empirical formula for baryon spectra in heavy-ion collisions and links it to quark distributions before hadronization, offering new phenomenological insights.

Findings

Universal formula fits wide pT range for multiple baryons

Reveals features of light and strange quark distributions

Challenges conventional fluid flow interpretation

Abstract

In an unconventional presentation of the data on the transverse momentum spectra of baryons produced in heavy-ion collisions, regularities are found that make possible the discovery of a universal formula valid for $p, \Lambda, \Xi$ and $\Omega$. The formula describes the baryon distributions over wide ranges of $p_T (0.5 \ ^<_\sim\ p_T \ ^<_\sim\ 5$ GeV/c) for $0.06 \ ^<_\sim\ \sqrt {s_{NN}} \ ^<_\sim\ 3$ TeV, except for very peripheral collisions. Some aspects of their empirical properties are derived in the recombination model, resulting in a revelation of some features of the light and strange quark distributions before hadronization. Interpretation of the inverse slopes of their exponential behavior leads to an implication that cannot accommodate the conventional description of fluid flow. This is mainly a study of phenomenology without detailed model input.