Dynamical quark recombination in ultrarelativistic heavy-ion collisions and the proton to pion ratio

Abstract

We study quark thermal recombination as a function of energy density during the evolution of a heavy-ion collision in a numerical model that reproduces aspects of QCD phenomenology. We show that starting with a set of free quarks (or quarks and antiquarks) the probability to form colorless clusters of three quarks differs from that to form colorless clusters of quark-antiquark and that the former has a sharp jump at a critical energy density whereas the latter transits smoothly from the low to the high energy density domains. We interpret this as a quantitative difference in the production of baryons and mesons with energy density. We use this approach to compute the proton and pion spectra in a Bjorken scenario that incorporates the evolution of these probabilities with energy density, and therefore with proper time. From the spectra, we compute the proton to pion ratio and compare to data at the highest RHIC energies. 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.

arXiv comment10 pages, 12 figures, version to appear in Phys. Rev. C

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• Dynamical heavy-quark recombination and the non-photonic single electron puzzle at RHIC
• $K^{\ast 0}$ and ${\Sigma }^{\ast }$ production in Au+Au collisions at $\sqrt{s_{NN}}=$ 200 GeV and 62.4 GeV
• Thermodynamic properties of the trigonometric Rosen-Morse potential and applications to a quantum gas of mesons
• Strange Baryon to Meson Ratio
• Statistical method in quark combination model
• Dynamical transition between two mesons and a tetraquark
• Proton to pion ratio at RHIC from dynamical quark recombination