The weak production of Λ hyperons from lepton-proton scattering

Abstract

We obtain the differential cross sections for the weak, strangeness changing processes, e − + p → Λ + ν e , μ − + p → Λ + ν μ , and τ − + p → Λ + ν τ as well as cross sections for the processes ν ¯ L + p → Λ + L + , where L stands for either a muon or a tau. We do this for electron energies from threshold to 2.0 GeV, for muon energies from near threshold to 5.0 GeV, for a tau energy of 20.0 GeV, and for muon antineutrino energies from threshold to 1.0 GeV and tau antineutrino energies near threshold. We discuss what might be learned from these reactions and obtain the contributions of the various form factors to these cross sections. We pay particular attention to the interference terms which may represent the only possibility of obtaining the weak magnetism form factor, F M , the pseudoscalar form factor, F P , and the form factor, F E . This latter form factor is forbidden by G-parity in the p ↔ n transition but is in principle permitted in the p ↔ Λ transition and its presence would therefore be of interest. Our calculation is a phenomenological one and makes use of SU(3) relations and Λ beta decay data.