System-size dependence of open-heavy-flavor production in nucleus-nucleus collisions at $\sqrt{{s}_{NN}}=200$ GeV

System-size dependence of open-heavy-flavor production in nucleus-nucleus collisions at $\sqrt{s_{N N}} = 200$ GeV

A. Adare et al. (PHENIX Collaboration)

Phys. Rev. C 90, 034903 – Published 5 September 2014

Abstract

The PHENIX Collaboration at the Relativistic Heavy Ion Collider has measured open-heavy-flavor production in $Cu + Cu$ collisions at $\sqrt{s_{N N}} = 200$ GeV through the measurement of electrons at midrapidity that originate from semileptonic decays of charm and bottom hadrons. In peripheral $Cu + Cu$ collisions an enhanced production of electrons is observed relative to $p + p$ collisions scaled by the number of binary collisions. In the transverse momentum range from 1 to 5 GeV/ $c$ the nuclear modification factor is $R_{A A} \sim 1.4$ . As the system size increases to more central $Cu + Cu$ collisions, the enhancement gradually disappears and turns into a suppression. For $p_{T} > 3$ GeV/ $c$ , the suppression reaches $R_{A A} \sim 0.8$ in the most central collisions. The $p_{T}$ and centrality dependence of $R_{A A}$ in $Cu + Cu$ collisions agree quantitatively with $R_{A A}$ in $d + Au$ and $Au + Au$ collisions, if compared at a similar number of participating nucleons $〈 N_{part} 〉$ .