Proton to pion ratio at RHIC from dynamical quark recombination

TL;DR

This paper models the dynamical process of quark recombination into protons and pions during relativistic heavy-ion collisions, using the string-flip model to explain the proton to pion ratio observed at RHIC.

Contribution

It introduces a dynamical quark recombination framework that accounts for energy density-dependent clustering probabilities in heavy-ion collisions.

Findings

Proton to pion ratio can reach unity with standard parameters.

The ratio is highly sensitive to initial evolution proper time.

Model aligns with RHIC data at high energy.

Abstract

We propose an scenario to study, from a dynamical point of view, the thermal recombination of quarks in the midsts of a relativistic heavy-ion collision. We coin the term dynamical quark recombination to refer to the process of quark-antiquark and three-quark clustering, to form mesons and baryons, respectively, as a function of energy density. Using the string-flip model we show that the probabilities to form such clusters differ. We apply these ideas to the calculation of the proton and pion spectra in a Bjorken-like scenario that incorporates the evolution of these probabilities with proper time and compute the proton to pion ratio, comparing to recent RHIC data at the highest energy. We show that for a standard choice of parameters, this ratio reaches one, though the maximum is very sensitive to the initial evolution proper time.