Radiative muon capture in nuclei

The energy spectra of photons following negative muon absorption in /sup 12/C, /sup 16/O, /sup 27/Al, /sup 40/Ca, /sup nat/Fe, /sup 165/Ho, and /sup 209/Bi have been measured with two NaI spectrometers. The branching ratios for the emission of high energy photons give information on the induced pseudoscalar coupling constant g/sub P/ in nuclear matter. The data for light nuclei are in agreement with the theoretical calculations using the nucleonic value of g/sub P/approx. =7g/sub A/ predicted by the partially conserved axial vector current hypothesis, while significantly lower values of g/sub P/ are required to fit the data of the heavier elements with presently existing theoretical predictions. Disregarding the remaining theoretical uncertainties, these results can be interpreted as a further indication of the renormalization of the nucleonic form factors inside the nucleus.