Sterile neutrino decay and the LSND experiment

Abstract

We propose a new explanation of the intriguing LSND evidence for electron antineutrino appearance in terms of heavy (mostly sterile) neutrino decay via a coupling with a light scalar and light (mostly active) neutrinos. We perform a fit to the LSND data, as well as all relevant null-result experiments, taking into account the distortion of the spectrum due to decay. By requiring a coupling g ∼ 10−5, a heavy neutrino mass m4 ∼ 100 keV and a mixing with muon neutrinos |Uµ4|2 ∼ 10−2, we show that this model explains all existing data evading constraints that disfavor standard (3 + 1) neutrino models.