New event types in a balloon-gorn cosmic ray experiment

Proton‐nucleus interactions at the mean energy of about 45 TeV and nucleus‐nucleus interactions at energies greater than 1 TeV/nucleon are being studied with a balloon born emulsion chamber. The multiplicities of charged secondaries, the fractional energy spectra and transferse momentum distribution of gamma rays, and the rapidity density in the central region are obtained. The features of inelastic proton‐nucleus interactions are as expected from extrapolations of measurements at lower energies. On the other hand, preliminary data on nucleus‐nucleus interactions indicate some features not expected by simple superposition of nucleon‐nucleon interactions. Examples of unusual phenomena include one event with multiplicity Ns=1000 and several events with apparent high PT particle productions.