MUON-CAPTURE IN SI-28 AND GP GA

Negative muon capture in Si-28 was used to determine the angular corre lation between the neutrino and the 1229 keV gamma-ray from the de-exc itation of the 2201 keV 1(+) level in Al-28. To suppress backgrounds i n the HPGe detectors, a coincidence was required with the 942 keV gamm a-ray in the de-excitation cascade detected in a Nal array, The extrac ted angular correlation coefficient alpha is 0.360 +/- 0.059, consiste nt with previous measurements. Using a recent shell model calculation employing a full Is-Od model space and the USD empirical interaction, this value of alpha implies a value for the induced pseudoscalar coupl ing of g(p)/g(a) = 0.0 +/- 3.2, substantially smaller than the predict ion of PCAC and pion-pole dominance. (C) 1997 Published by Elsevier Sc ience B.V.