LOW TRANSVERSE-MOMENTUM PHOTON PRODUCTION IN PROTON-NUCLEUS COLLISIONS AT 18 GEV C/

Inclusive single photon spectra have been measured in the transverse m omentum (p(T)) range from a few MeV/c up to approximately 1 GeV/c at v arious nucleon-nucleon center of momentum rapidities (y(NN)) in the in terval from -2.4<y(NN)<+0.5 in 18 GeV/c p-Be and p-W collisions. These distributions were used to estimate the inclusive p(T) and rapidity d istributions for pi(0) production over approximately the same kinemati c range. The measured photon spectra are compared with the expected di stribution of photons from pi(0) decays and hadronic bremsstrahlung in order to search for new sources of ''soft'' photons at low transverse momentum. The results indicate no anomalous sources of soft photons i n either p-Be or p-W interactions at these energies. The p-W data at f orward angles set a limit on any excess of low p(T) photons at <2.65 t imes hadronic bremsstrahlung at the 99% C.L.