Radiative Muon Capture by a Proton in Chiral Perturbation Theory

Abstract

The first measurement of the radiative muon capture (RMC) rate on a proton was recently carried out at TRIUMF. The TRIUMF group analyzed the RMC rate in terms of the theoretical formula of Beder and Fearing, and found the surprising result that the pseudoscalar coupling g_P is 1.5 times the value expected from PCAC. To assess the reliability of the theoretical framework used by the TRIUMF group to relate the RMC rate to the pseudoscalar form factor, we calculate the RMC rate in chiral perturbation theory, which provides a systematic framework to describe all the vertices involved in RMC, fulfilling gauge-invariance and chiral-symmetry requirements in a transparent manner. As a first step we present a chiral perturbation calculation at tree level which includes sub-leading order terms.

12 pages, LATEX (elsart.sty), 6 LATEX figures (axodraw.sty), 1 Postscript figure; to appear in PLB

Cited by in corpus (14)

• Axial structure of the nucleon
• Chiral Perturbation Theory and Baryon Properties
• The form factors of the nucleon at small momentum transfer
• Induced pseudoscalar coupling of the proton weak interaction
• Ordinary and radiative muon capture on the proton and the pseudoscalar form factor of the nucleon
• Capture rate and neutron helicity asymmetry for ordinary muon capture on hydrogen
• Ordinary muon capture on a proton in manifestly Lorentz invariant baryon chiral perturbation theory
• Radiative pion capture by a nucleon
• Ab initio calculation of muon capture on ${}^{24}$Mg
• An update of muon capture on hydrogen
• Analysis of ordinary and radiative muon capture in liquid hydrogen
• Polarized photons in radiative muon capture
• Gauge symmetric delta(1232) couplings and the radiative muon capture in hydrogen
• The high energy spectrum of internal positrons from radiative muon capture on nuclei