Nuclear modification factor of non-photonic electrons in heavy-ion collisions and the heavy-flavor baryon-to-meson ratio

TL;DR

This study investigates the nuclear modification factor of non-photonic electrons in heavy-ion collisions, considering heavy-flavor hadron decays and baryon-to-meson ratios, revealing that baryon enhancement has limited impact on electron suppression at high transverse momentum.

Contribution

It introduces a quark coalescence model analysis of heavy-flavor baryon-to-meson ratios and their effect on electron R_{AA} in heavy-ion collisions, highlighting the limited influence of baryon enhancement on high-momentum electron suppression.

Findings

Enhanced $ ext{Λ}_c/ ext{D}^0$ ratio peaks at low transverse momentum.

Baryon-to-meson ratio enhancement does not significantly suppress electron R_{AA} at high momentum.

Heavy quark energy loss remains the dominant suppression mechanism at large transverse momenta.

Abstract

The nuclear modification factor $R_{AA}$ of non-photonic electrons in ${Au} + {Au}$ collisions at $\sqrt{s_{NN}^{}} = 200$ GeV is studied by considering the decays of heavy-flavor hadrons produced in a quark coalescence model. Although an enhanced $\Lambda_c/D^0$ ratio is predicted by the coalescence model, it is peaked at small transverse momenta ($\sim 2$ GeV) due to the large difference between heavy and light quark masses. As a result, the enhanced $\Lambda_c/D^0$ ratio, which is expected to suppress the electron $R_{AA}$ as the branching ratio of $\Lambda_c$ decay into electrons is smaller than that of $D^0$, does not lead to additional suppression of the electron $R_{AA}$ at large transverse momenta ($\ge 5$ GeV), where the suppression is mainly due to heavy quark energy loss in produced quark-gluon plasma. Also, the enhanced $\Lambda_b/\bar{B}^0$ ratio predicted by the coalescence model has even smaller effect on the non-photonic electron $R_{AA}$ as bottom baryons and mesons have similar branching ratios for semi-leptonic decays into electrons.