Photon and η production in p + Pb and p + C collisions at sNN=17.4 GeV

Abstract Measurements of direct photon production in p + Pb and p + C collisions at s NN = 17.4 GeV are presented. Upper limits on the direct photon yield as a function of p T are derived and compared to the results for Pb + Pb collisions at s NN = 17.3 GeV . The production of the η meson, which is an important input to the direct photon signal extraction, has been determined in the η → 2 γ channel for p + C collisions at s NN = 17.4 GeV .