Open charm hadron production via hadronic decays at STAR

TL;DR

This paper reports measurements of open charm hadron production via hadronic decays at STAR, confirming initial hard scattering dominance and scaling behavior in proton-proton and gold-gold collisions at RHIC energies.

Contribution

It presents new measurements of D mesons in p+p and Au+Au collisions, supporting the understanding of charm production mechanisms at RHIC.

Findings

Charm cross section in Au+Au scales with binary collisions.

Measured D meson spectra in p+p and Au+Au collisions.

Supports initial gluon fusion as dominant charm production process.

Abstract

Heavy quarks are a unique probe to study the medium produced in ultra-relativistic heavy ion collisions. The dominant process of charm quark production at RHIC is believed to be initial gluon fusion which can be calculated in the perturbative QCD. The upper limit of FONLL calculation seems to be in good agreement with charm cross section measurements at mid-rapidity in $p+p$ collisions at $\sqrt{s_{NN}}$ = 200 GeV provided by STAR. The same measurement in Au+Au collisions at equal energy reveals the number-of-binary-collisions scaling of charm cross section indicating that charm production is dominated by initial hard scatterings. In this article, we report the measurements of $D^{0}$, $D^{*}$ in $p+p$ at 0.6 GeV/$c < p_T < 6$ GeV/$c$ and $D^0$ in Au+Au collisions at 0.2 GeV/$c < p_T < 5$ GeV/$c$ via hadronic decays $D^{0}\rightarrow K^-\pi^+,\ D^{*+}\rightarrow D^0\pi^+\rightarrow K^-\pi^+\pi^+$ at mid-rapidity $|y|<1$. {abstract}