Positron production by muon neutrinos BEBC filled with a neon-hydrogen mixture

For e + energy > 0.3 GeV and 10 GeV ƒ = (v μ + Ne → μ − e + )/(v μ + Ne → μ − ) = (0.41 ± 0.15)% ; (ii) 1.2 ± 0.5 neutral strange particles are produced per μ − e + event; (iii) the lifetime of possible positron-parent particles is −10 s (90% C.L.); (iv) the cross section for direct e + production via the neutral current is + , decaying into e + … is −3 times that for μ − production, implying M (L + ) > 10 GeV.