Production of Large-Transverse-Momentum Gamma Rays inppCollisions from 50 to 400 GeV

Abstract

We have measured $\frac{d^2{\sigma }_{\gamma }}{\mathrm{dkd}\Omega }$ for the reaction $p+p\to \gamma +\mathrm{anything}$ at incident proton energies from 50 to 400 GeV. The experiment was performed in the National Accelerator Laboratory internal target area, using a lead-glass total-absorption counter. The cross sections show a deviation from simple exponential behavior in $p_t$ for incident proton energies above 50 GeV and $p_t$ greater than about 1 GeV/c. We present preliminary results on the energy dependence of this effect.