THEORY OF PARITY VIOLATION IN COMPOUND NUCLEAR-STATES - ONE-PARTICLE ASPECTS

In this work we formulate the reaction theory of parity violation in c ompound nuclear states using Feshbach's projection operator formalism. We derive in this framework a complete set of terms that contribute t o the longitudinal asymmetry measured in experiments with polarized ep ithermal neutrons. We also discuss the parity violating spreading widt h resulting from this formalism. We then use the above formalism to de rive expressions which hold in the case when the doorway state approxi mation is introduced. In applying the theory we limit ourselves in thi s work to the case when the parity violating (PV) potential and the st rong interaction are one body. In this approximation, using as the doo rway the giant spin-dipole resonance and employing well-known optical potentials and a time-reversal even, parity odd one-body interaction w e calculate or estimate the terms we derived. Among others, we evaluat e numerically a new ''direct'' term and the channel coupling term firs t derived by Lewenkopf and Weidenmuller, this in addition to the evalu ation of the main ''compound'' term. In our calculations we explicitly orthogonalize the continuum and bound wave functions. We find the eff ects of orthogonalization to be very important. Our conclusion is that the present one-body theory cannot explain the average longitudinal a symmetry found in the recent polarized neutron experiments. We also co nfirm the discrepancy, first pointed out by Auerbach and Bowman, that emerges, between the calculated average asymmetry and the parity viola ting spreading width, when distant doorways are used in the theory.