Probing Hot and Dense Matter with Charm and Bottom Measurements with PHENIX VTX Tracker

We present the first measurements of the nuclear modification factor (RAA) for flavor-separated b,c-quark electrons in Au + Au collisions at √(sNN)=200 GeV. The newly installed Silicon Vertex Tracker is used to measure the distance of closest approach distributions of electrons at midrapidity (|η|<0.35) over the transverse momentum range 1<pTe<5 GeV/c. From this, the relative fraction of bottom (b) and charm (c) quarks is determined in both the p+p and Au + Au collision systems, which form the basis of the measured RAA. In p+p, we observe that a FONLL perturbative QCD calculation of b→e/(c→e+b→e) ratio is in good agreement with the data. In Au + Au, the data imply a large suppression of b→e or a large modification of B meson pT distributions, which implies very interesting physics of B mesons in Au + Au collisions