Conservation of Isotopic Spin and Isotopic Gauge Invariance

must then consider either the absolute value of the C"(p,pl) cross section or that of the AP7(p, 3prs) cross section (or both) to be in error. We have rather arbitrarily chosen to base our data on the 10.8-mb value for the AP'(p, 3prs) cross section at 420 Mev. Figure 1 shows that the cross section of the C"(p,pcs) C" reaction is a fairly insensitive function of the energy of the incident proton in the energy range studied here. Since similar results were found for the production of Na", Na", and F" from aluminum and for Be~ formation from carbon, 6 it appears to be generally true that the probability of ejecting a small number of nucleons from a small nucleus remains substantially constant over a range of bombarding energies from a few hundred Mev to at least 3 Bev. This implies that the probability that the incident particle leaves behind a relatively small amount of energy (&100 Mev) in the ieitia/ interaction with the nucleus is relatively constant over the wide energy range studied. However within this energy range meson production increases very markedly with energy and becomes a probable process. If the nucleus is large these mesons would have a good chance of being reabsorbed in the nucleus in which they were produced. This would result in a shift of the maximum in the total energy deposition spectrum to higher values, and reactions in which only a small