Measurement of direct photon production at large transverse momentum in π−p, π+p, and pp collisions at 300 GeV/c

de Marzo, C.; de Palma, M.; Favuzzi, C.; Maggi, G.; Nappi, E.; Posa, F.; Ranieri, A.; Selvaggi, G.; Spinelli, P.; Bamberger, A.; Fuchs, M.; Heck, W.; Loos, C.; Marx, R.; Runge, K.; Skodzek, E.; Weber, C.; Wülker, M.; Zetsche, F.; Artemiev, V.; Galaktionov, Yu.; Gordeev, A.; Gorodkov, Yu.; Kamyshkov, Yu.; Plyaskin, V.; Pojidaev, V.; Shevchenko, V.; Shumilov, E.; Tchudakov, V.; Bunn, J.; Fent, J.; Freund, P.; Gebauer, J.; Glas, M.; Polakos, P.; Pretzl, K.; Schouten, T.; Seyboth, P.; Seyerlein, J.; Vesztergombi, G.

doi:10.1103/PhysRevD.36.8

Cross sections for inclusive direct photon production in -p, +p, and pp collisions at 300 GeV/c are measured at transverse momenta pT up to 7 GeV/c (xT=0.6). For -pX also the rapidity distribution is presented. The cross-section ratio (-pX)/(+pX) is found to be 1 at pT=4 GeV/c and rises with increasing pT. This observation signals the occurrence of valence-quarkantiquark annihilation. The results are in good agreement with QCD predictions.

Measurement of direct photon production at large transverse momentum in π−p, π+p, and pp collisions at 300 GeV/c / de Marzo, C.; de Palma, M.; Favuzzi, C.; Maggi, G.; Nappi, E.; Posa, F.; Ranieri, A.; Selvaggi, G.; Spinelli, P.; Bamberger, A.; Fuchs, M.; Heck, W.; Loos, C.; Marx, R.; Runge, K.; Skodzek, E.; Weber, C.; Wülker, M.; Zetsche, F.; Artemiev, V.; Galaktionov, Yu.; Gordeev, A.; Gorodkov, Yu.; Kamyshkov, Yu.; Plyaskin, V.; Pojidaev, V.; Shevchenko, V.; Shumilov, E.; Tchudakov, V.; Bunn, J.; Fent, J.; Freund, P.; Gebauer, J.; Glas, M.; Polakos, P.; Pretzl, K.; Schouten, T.; Seyboth, P.; Seyerlein, J.; Vesztergombi, G.. - In: PHYSICAL REVIEW D. - ISSN 0556-2821. - STAMPA. - 36:1(1987), pp. 8-15. [10.1103/PhysRevD.36.8]