Investigations of weak couplings measuring angular correlations in mu capture: Impact of nuclear models

(eng) The angular correlations were investigated measuring with high-precision HPGe detectors γ-lines following the ordinary muon capture (OMC) on 28Si and 16O. The Doppler-broadened shapes of these lines are sensitive to the weak couplings as well as to the nuclear matrix elements (NME) of OMC transitions. A considerable quenching of the induced pseudoscalar form-factor g P and a nonzero value of sum of scalar couplings C S+g S are reported contradictory to the postulates of the Standard Model. However, the questions of reliability of the NME used to extract the weak couplings from the experimentally measured correlation parameters are still open. Future steps in order to solve this problem are discussed.