Production of protons with momenta 0.2--0.5 GeV/c emitted backward in the lab in p-barA interactions at 40 GeV/c

A five-meter streamer chamber with internal nuclear targets has been used to study the production of protons with momenta 0.2--0.5 GeVc emitted into the backward hemisphere in the lab in p-barA interactions at 40 GeVc. It has been established that the fraction of events with backward-emitted protons is proportional to A13 , where A is the mass number of the target nucleus. On the average for every two slow protons emitted into the forward hemisphere in the lab, one proton is emitted into the backward hemisphere, regardless of the nucleus. In the distributions of the number of backward-emitted protons, and also of negatively charged particles, N/sub p/ scaling is observed, in agreement with the additive quark model. It is shown that the intranuclear cascade plays an important role in the production of backward-emitted protons