Hadron production from quark coalescence and jet fragmentation

Transverse momentum spectra of pions, protons, and antiprotons in $\mathrm{Au}+\mathrm{Au}$ collisions at intermediate RHIC energy $\sqrt{s_{\mathit{NN}}}=62\mathrm{GeV}$ are studied in a model that includes both quark coalescence from the dense partonic matter and fragmentation of the quenched perturbative minijet partons. The resulting baryon to meson ratio at intermediate transverse momenta is predicted to be larger than that seen in experiments at higher center of mass energies.

Figure 1

(Color online) Hadron transverse momentum spectra from central $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{s_{\mathit{NN}}}=62\mathrm{GeV}$. Predicted results are for pions (solid line), protons (dash-dotted line), and antiprotons (dashed line). Experimental ${\pi }^0$ (filled circles) and proton (open squares) data at $\sqrt{s_{\mathit{NN}}}=200\mathrm{GeV}$ [40, 42] are shown for reference. Inset: The ratio $r(p_T)$ of the contribution from quark coalescence to that from both quark coalescence and minijet fragmentation for π (solid line), p (dash-dotted line), and $\overline{p}$ (dashed line).

Figure 2

(Color online) Same as Fig. 1 for the ratios of proton (solid line) and antiproton (dashed line) to pion spectra.