Cross sections for trinucleon photoeffect

Abstract

Several new examples of electric dipole transitions to final isopsin 3/2 are calculated using the Fabre-Levinger formalism: (i) the Volkov potential (Serber exchange) gives an integrated cross section 4% higher than the O'Connell-Prats sum rule; (ii) the V/sup x/ potential (zero force in odd-parity two-body states) gives a /sup 3/H photoeffect cross section close to that found by Fabre and Levinger for /sup 3/He; (iii) transitions to an uncoupled grand orbital 3 are several percent of those to grand orbital 1. Addition of the cross sections for uncoupled states gives poor agreement with the coupled calculation of Fang et al.; (iv) a V/sup x/ potential (Wigner-Bartlett exchange) gives an integrated cross section 5% higher than the Thomas-Reichl-Kuhn value. We also calculate for final isospin 1/2, neglecting coupling to two-body breakup. The V/sup x/ potential (zero force in odd-parity two-body states) gives an integrated cross section 23% higher than the O'Connell-Prats value. A Wigner-Bartlett mixture gives a 23% disagreement with the Thomas-Reiche-Kuhn sum rule. The calculated cross section (summed for both isospin states) has a higher and narrower peak than that measured by Gorbonov (summed for two-body and three-body breakup).