MEASUREMENT OF THE INDUCED PSEUDOSCALAR FORM FACTOR IN THE CAPTURE OF POLARIZED MUONS BY SI NUCLEI

摘要

The observation with high-resolution Ge detectors of the 1229 and 2171 keV gamma-rays emitted after the Si-28(mu, nu)Al-28(1(+),2202 keV) reaction allowed us to determine the nuclear-amplitude ratio x = M(2)/M(-1) characteristic of this muon-capture reaction. Using the nuclear-structure dependent evaluation of various correction terms (model of CiechBnowicz), our result x = +0.254+/-0.034 provides for the induced pseudoscalar coupling gp the ratio g(P)/g(A)(0.848m(mu)(2)) = 3.4+/-1.0, to be compared to the PCAC prediction of g(P)/g(A) = 7 The model dependence of this apparent quenching remains to be assessed. [References: 61]