Nuclear Photostar Production

Cross sections for photonuclear star production are computed phenomenologically for photomeson production in a nucleus followed by meson absorption in the same nucleus. Results are found for values of the mean free path of mesons in nuclear matter of 4×${10}^{-13\mathrm{}}$ cm and 8×${10}^{-13\mathrm{}}$ cm as a function of atomic mass number and photon energy. The process accounts for a large part of observed photostars with three and more prongs for elements as heavy as Br, but for only a small part for elements as light as O.