A measurement of the photon asymmetry (αγ) in radiative muon capture RMC on 40Ca has been carried out at TRIUMF. Negative muons were stopped in a 40Ca target and the resulting RMC photons were then converted by a 5-cm thick NaI detector placed immediately in front of our main NaI detector, a cylindrical crystal of diameter 46 cm and depth 51 cm. The data sample consisted of 5200 high-energy (57 MeV<E γ <95 MeV) RMC photon candidates. Our measured value for the energy-averaged photon asymmetry is αγ = 1.00±0.23. The extracted values for the induced pseudoscalar coupling constant (gP) based on this photon asymmetry measurement are g P/gA <8.0, utilizing the impulse approximation IA model, and gP/gA <14.5 in terms of the modified impulse approximation (MIA) model. The two extracted values, although both consistent with the Goldberger-Treiman value of gP/gA ≈ 7, are considerably different, indicating a significant theoretical model dependency.
|Number of pages||3114464|
|Journal||Physical Review C - Nuclear Physics|
|State||Published - Sep 2003|
ASJC Scopus subject areas
- Nuclear and High Energy Physics