Prompt Neutrino Production in 400-{GeV} Proton Copper Interactions

Abstract The prompt electron neutrino and muon neutrino fluxes from proton copper interactions at 400 GeV/ c proton momentum have been measured. The asymmetry between the prompt electron (anti) neutrino and the prompt muon (anti) neutrino event rates above 20 GeV is A e μ = (N e − N μ (N c + N μ ) = 0.07 ± 0.08 corresponding to an N e / N μ ratio of 1.14 −0.16 −0.19 . The cross section weighted charge asymmetry for electrons and muons combined is A ν ν = 0.15 ± 0.08 . The number of D decays into ν e and ν μ is (4.1 ± 0.9) × 10 −4 per incident proton. No evidence for ν τ interactions was found.