The study of heavy flavors via non-photonic electrons in STAR

TL;DR

This paper investigates heavy quark energy loss in quark-gluon plasma via non-photonic electron spectra in various collision systems at RHIC, revealing unexpected suppression patterns challenging existing theories.

Contribution

It provides new measurements of non-photonic electrons in Cu+Cu collisions and compares them with p+p and Au+Au data to test system size effects on heavy quark energy loss.

Findings

Strong suppression of non-photonic electrons in central Au+Au collisions.

Preliminary Cu+Cu spectra are being analyzed for system size dependence.

Current models do not fully explain the observed suppression patterns.

Abstract

The strong suppression of hadrons with high transverse momenta in central Au+Au collisions observed at RHIC is generally interpreted as a consequence of energy loss of energetic partons in the hot and dense matter before fragmenting. The study of heavy quark production tests our understanding of energy loss mechanisms. Heavy quarks were expected to lose less energy in the medium than light quarks and gluons due to the suppression of small-angle gluon radiation. However, the high transverse momentum non-photonic electron spectra, which are dominated by semi-leptonic decays of heavy quarks, show a strong suppression in central Au+Au collisions as well. Current theoretical models do not satisfactory explain this observation. Preliminary non-photonic electron spectra are being extracted for Cu+Cu collisions at $\sqrt{s_{NN}}$ = 200 GeV. They are compared to the non-photonic electron yields from p+p and Au+Au collisions at the same collision energy. This provides a direct experimental test of the dependence of the non-photonic electron yield on collision system size.