Abstract: Non-photonic electron production in Cu+Cu and Au+Au collisions at GeV at STAR.

High-energy nucleus-nucleus collisions at RHIC allow the study of the behavior of nuclear matter at high temperatures, where a new phase of matter, the quark-gluon plasma is predicted to exist. All partons are thought to lose energy through gluon radiation as they pass through the hot and dense nuclear matter; however heavy quarks are expected to lose less energy than light quarks and gluons due to the suppression of small-angle gluon radiation. Non-photonic electrons (proxies for heavy quarks) are suppressed by a factor of ~5 in central Au+Au collisions relative to $p+p$ collisions at GeV. This suppression is larger than most current theoretical predictions and has led to a re-examination of heavy-quark energy loss in the medium. A measurement of the non-photonic electron spectrum in Cu+Cu collisions at GeV is presented. The spectrum is compared to the non-photonic electron yields from $p+p$ and Au+Au collisions at the same energy to extract the nuclear modification factor and the dependence of the non-photonic electron yield on system size.