Capture rate and neutron helicity asymmetry for ordinary muon capture on hydrogen
Abstract
Applying heavybaryon chiral perturbation theory to ordinary muon capture (OMC) on a proton, we calculate the capture rate and neutron helicity asymmetry up to nexttonexttoleading order. For the singlet hyperfine state, we obtain the capture rate Γ_{0}=695 s^{1} while, for the triplet hyperfine state, we obtain the capture rate Γ_{1}=11.9 s^{1} and the neutron asymmetry α_{1}=0.93. If the existing formalism is used to relate these atomic capture rates to Γ_{liq}, the OMC rate in liquid hydrogen, then Γ_{liq} corresponding to our improved values of Γ_{0} and Γ_{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 difficulty may be correlated to the specious anomaly recently reported for μ^{}+p>n+ν_{μ}+γ, 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 Γ_{liq}.
 Publication:

Physical Review C
 Pub Date:
 December 2000
 DOI:
 10.1103/PhysRevC.63.015203
 arXiv:
 arXiv:nuclth/0008003
 Bibcode:
 2000PhRvC..63a5203A
 Keywords:

 24.85.+p;
 11.80.Cr;
 12.39.Fe;
 23.40.s;
 Quarks gluons and QCD in nuclei and nuclear processes;
 Kinematical properties;
 Chiral Lagrangians;
 Beta decay;
 double beta decay;
 electron and muon capture;
 Nuclear Theory;
 High Energy Physics  Phenomenology
 EPrint:
 14 pages, 1 figure