Nuclear Structure Effects on Weak Nuclear Form Factors of 0+-0- Transitions in A=16 System

Abstract

The ratio of muon-capture rate to beta-decay rate in the trans1t10ns 160 (o+: ground) 1'N co-: 120 ke V) is calculated with realistic nuclear models and with an exact formalism for lepton wave functions. In contrast to the results with no ground-state correlation, the calculated ratio is strongly reduced in agreement with the experimental data. Our results are compatible with the PCAC hypothesis. The effects of the exchange currents are found to be not large. § l. Introduction Among vanous nuclear weak processes the o+ -0- transitions are unique transi­ tions which are governed completely by the nuclear axial vector current. Their rates are, therefore, sensitive to the detailed dynamics of this current, and the transitions between 160 co+: ground) and 16N co··: 120 ke V) are well-known. At the early time, the muon capture rate in 160 leading to 16N co-) was