Photon and Eta Production in p+Pb and p+C Collisions at sqrt{sNN} = 17.4 GeV

Measurements of direct photon production in p+Pb and p+C collisions at $\sqrt{s_{\mathrm{N}\mathrm{N}}}=17.4\mathrm{G}\mathrm{e}\mathrm{V}$ are presented. Upper limits on the direct photon yield as a function of $p_{\mathrm{T}}$ are derived and compared to the results for Pb+Pb collisions at $\sqrt{s_{\mathrm{N}\mathrm{N}}}=17.3$ GeV. The production of the $\eta$ meson, which is an important input to the direct photon signal extraction, has been determined in the $\eta \to 2\gamma$ channel for p+C collisions at $\sqrt{s_{\mathrm{N}\mathrm{N}}}=17.4\mathrm{G}\mathrm{e}\mathrm{V}$.