Photon and neutral pion production in Au+Au collisions at √sNN=130 GeV

Abstract

We report inclusive photon measurements about midrapidity (|y|<0.5) from Au+197 Au197 collisions at √sNN=130 GeV at RHIC. Photon pair conversions were reconstructed from electron and positron tracks measured with the Time Projection Chamber (TPC) of the STAR experiment. With this method, an energy resolution of ΔE/E≈2% at 0.5 GeV has been achieved. Reconstructed photons have also been used to measure the transverse momentum (pt) spectra of π0 mesons about midrapidity (|y|<1) via the π0→ γγ decay channel. The fractional contribution of the π0→ γγ decay to the inclusive photon spectrum decreases by 20%±5% between pt=1.65 GeV/c and pt=2.4 GeV/c in the most central events, indicating that relative to π0→ γγ decay the contribution of other photon sources is substantially increasing.