Proton resonance spectroscopy: Progress report, June 15, 1987-January 31, 1988

Resonances in nuclei have provided the major testing ground for random-matrix theory. With the recent demonstration that certain quantum chaotic systems also appear to be described by random-matrix theory, the possibility that the nucleus is itself a quantum chaotic system has been suggested. Although showing no direct relation to quantum chaos, some of the work described herein has examined more closely the role of a random-matrix description of nuclei. We have shown that the body of resonance amplitude data shows overall agreement with the key prediction of random-matrix theory that the amplitudes should obey a Gaussian distribution. We also have new data which for the first time show correlations between entrance channels. The role of energy level fluctuations in 26Al is being examined to see if random-matrix theory can provide a good description at energies near the ground state. We also hope to learn something about the role of isospin symmetry in this nucleus by analyzing fluctuations of the T = 0 and T = 1 levels separately. The role of spectroscopy of individual levels in studying symmetries has also been investigated. An attempt to populate the lowest isospin 2 state in 40Ca via the isospin-forbidden p + 39K reaction has been made. Finally, detailed calculations on the role of nuclear spectroscopy in experiments to measure parity mixing in slow neutron resonances have been performed; these calculations reveal the necessity of a thorough understanding of the spectroscopy of the states involved in order to extract the parity-nonconserving matrix element. 29 refs