Comparison of direct γ production in antipp and pp reactions at √s = 24.3 GeV in 4 <PT<6 GeV/c (.3<xT<.5)

Direct photons have been studied in both antipp and pp interactions at √s = 24.3 GeV, in the transverse momentum range 4 to 6 GeV/c (0.3<xT<0.5) for-0.4<y<1.2. The experiment was performed using an internal hydrogen jet target in the CERN SpantipS Collider. Preliminary cross-sections in antipp and in pp are presented. For the first time the difference antipp-pp has been measured and is compared to theoretical predictions. A preliminary determination of the gluon structure function is obtained. Prospects for improvements in the UA6 data are also discussed