Neutrons from the capture of a polarized mu meson

摘要: Abstract The angular distribution of the neutrons from capture by a spinless nucleus totally polarized mu meson in 1s Bohr orbit, is calculated via two single-particle nuclear models, termed “modified Fermi gas” and “square well.” A direct 4-fermion coupling, with left-handed neutrino, represents weak interaction. major results depend on Fermi, Gamow-Teller, pseudoscalar coupling constants: cF, cG, cP. 1 + κ( C − ) cos θ , where angle muon's spin to neutron's momentum, ± = |c F | 2 2|c G ( p 2M )c P neutrino's energy, M rest energy nucleon, κ asymmetry reduction factor. calculations, performed for Ca40 Pb208, employ sea protons μ− → ν n produce at localized zone nucleus, which are followed through surface geometrical optics. Those escape this stage calculation “direct neutrons,” restricted ∼0.7. Due total internal reflection attenuation, most don't directly. Captured assumed excite boil-off, isotropic, strongly dominates lower 3 neutron spectrum. top quarter spectrum nevertheless relatively free boil-off. “square-well” O16, Si28, Ca40, eigenfunctions real square well finite depth nucleons, spherical harmonic expansion up g-waves, inclusive, neutrino plane wave. ranges several ∼30 percent. In such model upper shells found dominate captures productions neutrons. case rarefied hydrogen treated an Appendix.