Recent Heavy-Flavor results at STAR

TL;DR

This paper reports recent heavy-flavor results at STAR, including non-photonic electron yields, J/psi spectra, and correlations, providing insights into production mechanisms and nuclear effects in high-energy collisions.

Contribution

It presents new measurements of heavy-flavor observables at STAR, including electron yields, J/psi spectra, and correlations, with improved detector conditions and high luminosity data.

Findings

NPE yields are consistent with previous results after detector material reduction.

J/psi spectra follow x_T scaling at high pT but violate it at low pT.

J/psi-hadron correlations suggest less than 17% B-meson contribution.

Abstract

We present the recent results on non-photonic electron (NPE) yields from RHIC run8 p+p collisions. The $e/\pi$ ratio as a function of $p_T$ in run8 with a factor of 10 reduction of the inner detector material at STAR is found to be consistent with those results from run3 taking into account the NPE from charm leptonic decay and the difference of photonic electron yield from photon conversion in detector material. \Jpsi spectra in \pp and \cucu collisions at \sNN = 200 GeV with high sampled luminosity \Jpsi spectrum at high-\pT follows $x_T$ scaling, but the scaling is violated at low \pT. $J/\psi$-hadron correlations in \pp collisions are studied to understand the \Jpsi production mechanism at high $p_T$. We observed an absence of charged hadrons accompanying \Jpsi on the near-side, in contrast to the strong correlation peak in the di-hadron correlations. This constrains the $B$-meson contribution and jet fragmentation to inclusive \Jpsi to be ${}^{<}_{\sim}17%$. Yields in minimum-bias \cucu collisions are consistent with those in \pp collisions scaled by the underlying binary nucleon-nucleon collisions in the measured \pT range. Other measurements and future projects related to heavy-flavors are discussed.