High-energy neutrons emitted after muon capture in 40Ca

Abstract

The energy spectrum of neutrons emitted after ω-capture in 40Ca has been measured up to the kinematical endpoint of 92 MeV using two recoil telescopes. The neutron energy was deduced from the energy and angle of recoiling protons which originate from interactions of neutrons in a liquid scintillator. The neutron spectrum above 30 MeV is reproduced fairly well by a simple calculation based upon a reaction mechanism in which the muon is adsorbed, like in pion capture, by a pair of nucleons.