Eur. Phys. J. A (2007) 33: 7-10
https://doi.org/10.1140/epja/i2007-10392-7

Regular Article - Nuclear Structure and Reactions

Chiral invariant phase space event generator

Nuclear muon capture at rest

CERN, 1211, Geneva, Switzerland

^* e-mail: Mikhail.Kossov@cern.ch

Received: 16 March 2007
Accepted: 6 June 2007
Published online: 22 June 2007

Abstract

The Geant4 CHIPS model simulates both decay and nuclear capture of negative muons. In hadron level models the muon is captured by a proton, p(μ,ν_μ)n , and the neutron transfers to the nucleus only 5MeV, which is not enough to split a nucleon from the nucleus, while the measured spectra of emitted nucleons reach 80MeV. In CHIPS, which considers asymptotically free quark-partons, the muon can be captured by a quark, u(μ,ν_μ)d , and transfers 52MeV to the nucleus. This capture mechanism fits the main part of the nucleon spectra, while the high-energy part of the spectra is not fitted. A precise fit of the high-energy part of the nucleon spectra can be made if the muon decay μ → d¯ν_μ is taken into account.