Capture rate and neutron helicity asymmetry for ordinary muon capture on hydrogen

Abstract

Applying heavy-baryon chiral perturbation theory to ordinary muon capture (OMC) on a proton, we calculate the capture rate and neutron helicity asymmetry up to next-to-next-to-leading order. For the singlet hyperfine state, we obtain the capture rate Gamma_0 = 695 sec^{-1} while, for the triplet hyperfine state, we obtain the capture rate Gamma_1 = 11.9 sec^{-1} and the neutron asymmetry alpha_1 = 0.93. If the existing formalism is used to relate these atomic capture rates to Gamma_{liq}, the OMC rate in liquid hydrogen, then Gamma_{liq} corresponding to our improved values of Gamma_0 and Gamma_1 is found to be significantly larger than the experimental value, primarily due to the updated larger value of g_A. We argue that this apparent difficulity may be correlated to the specious anomaly recently reported for mu^- + p to n + nu_mu + gamma, and we suggest a possibility to remove these two "problems" simply and simultaneously by reexamining the molecular physics input that underlies the conventional analysis of Gamma_{liq}.

14 pages, 1 figure

References in corpus (2)

• Virtual photons in baryon chiral perturbation theory
• Nuclear Muon Capture on the Proton and 3He within the Standard Model and Beyond

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• Electroweak Radiative Corrections to Muon Capture
• Comprehensive asymmetric dark matter model
• Ordinary muon capture on a proton in manifestly Lorentz invariant baryon chiral perturbation theory
• Fundamental measurements with muons - View from PSI
• Cluster effective field theory and nuclear reactions
• An update of muon capture on hydrogen
• Analysis of ordinary and radiative muon capture in liquid hydrogen
• Polarized photons in radiative muon capture
• Ordinary Muon Capture in Hydrogen Reexamined
• The muon capture rate on hydrogen and the values of $g_A$ and $g_{\pi NN}$