Nuclear Modification of Electron Spectra and Implications for Heavy Quark Energy Loss inAu+AuCollisions atsNN=200GeV

The PHENIX experiment has measured midrapidity ($|\ensuremath{\eta}|l0.35$) transverse momentum spectra ($0.4l{p}_{T}l5.0\text{ }\text{ }\mathrm{GeV}/c$) of electrons as a function of centrality in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{{s}_{NN}}=200\text{ }\text{ }\mathrm{GeV}$. Contributions from photon conversions and from light hadron decays, mainly Dalitz decays of ${\ensuremath{\pi}}^{0}$ and $\ensuremath{\eta}$ mesons, were removed. The resulting nonphotonic electron spectra are primarily due to the semileptonic decays of hadrons carrying heavy quarks. Nuclear modification factors were determined by comparison to nonphotonic electrons in $p+p$ collisions. A significant suppression of electrons at high ${p}_{T}$ is observed in central $\mathrm{Au}+\mathrm{Au}$ collisions, indicating substantial energy loss of heavy quarks.