Further analysis of a direct soft photon excess in π-p interactions at 280 GeV/c

In this Letter we present additional experimental characteristics of anomalous soft photon radiation observed in pi(-)p interactions at 280 GeV/c in the CERN experiment WA91, together with a re-calculated ratio of the observed direct soft photon signal to the expected level of the hadronic inner bremsstrahlung, which is found to be 5.3 +/- 1.0. The other presented characteristics, energy dependence and angular distributions of direct soft photons, show the similarity of the observed signal to the expected hadronic bremsstrahlung behaviour. (C) 2002 Elsevier Science B.V. All rights reserved.