Journal article
Radiative muon capture on hydrogen and the induced pseudoscalar coupling
G Jonkmans, S Ahmad, DS Armstrong, G Azuelos, W Bertl, M Blecher, CQ Chen, P Depommier, BC Doyle, T von Egidy, TP Gorringe, P Gumplinger, MD Hasinoff, AJ Larabee, JA Macdonald, SC Mc Donald, M Munro, JM Poutissou, R Poutissou, DH Wright Show all
Physical Review Letters | AMERICAN PHYSICAL SOC | Published : 1996
Abstract
The first measurement of the elementary process μ-p→υμnγ is reported. A photon pair spectrometer was used to measure the partial branching ratio (2.10±0.22)×10-8 for photons of k > 60 MeV. The value of the weak pseudoscalar coupling constant determined from the partial branching ratio is gp(q2=-0.88m2μ)=(9.8±0.7±0.3)·ga(0), where the first error is the quadrature sum of statistical and systematic uncertainties and the second error is due to the uncertainty in λop, the decay rate of the ortho to para pμp molecule. This value of g_p is 1.5 times the prediction of PCAC and pion-pole dominance. © 1996 The American Physical Society.