Direct production of photons with large transverse momentum in proton-proton collisions

The direct production of photons with large transverse momentum is examined in a modified quark-fusion model which incorporates a realistic jet structure. The model, which accounts well for the pion data, predicts a sizable yield of direct photons. We expect a $\frac{\gamma }{{\pi }^0}$ ratio varying from 5% up to 20% in the Fermilab and CERN ISR energy range.