MEASUREMENT OF THE INDUCED PSEUDOSCALAR COUPLING USING RADIATIVE MUON-CAPTURE ON HYDROGEN

The photon energy spectrum from the elementary process mu(-)p-->nu(mu) n gamma was measured using a photon pair-spectrometer at the TRIUMF cy clotron. Various sources of backgrounds are discussed in detail and ev aluated. From the final spectrum the partial branching ratio R-gamma a nd the pseudoscalar coupling g(p) were extracted. The values obtained are R-gamma(k>60 MeV)=(2.10+/-0.21)X 10(-8) and g(p)(q(2)=-0.88m(mu)(2 ))=(9.8 +/-0.7+/-0.3)g(a)(0), respectively. The first error is the qua drature sum of statistical and systematic errors, while the second err or is due to the uncertainty in lambda(op), the transition rate of the p mu p molecule from ortho to para states. This measurement of g(p), the most precise to date, agrees with all but one of the previous meas urements. However it is 1.46 times the value predicted by the partiall y conserved axial current hypothesis and pion pole dominance.