Up-down asymmetry of neutral current events as a diagnostic for νμ− νst versus νμ− ντ oscillations

Abstract

We show that the asymmetry in the neutral current events (e.g. νN→ νNπ 0) can be used to discriminate between ν μ − ν τ and ν μ − ν st mixing as being responsible for the atmospheric neutrino anomaly. Specifically, A N vanishes for ν μ − ν τ mixing and is about 2/3 A μ for ν μ − ν st mixing. We also comment on the possibility of mixing of all three neutrinos (i.e. ν μ − ν τ − ν st) which can give a muon asymmetry as large as 1/2.