Further evidence for neutrino oscillations from LSND: the νμ → νe decay-in-flight channel

Abstract

A search for ν μ → ν e oscillations has been conducted at the Los Alamos Meson Physics Facility (LAMPF) using ν μ from π + decay in flight (DIF). An excess in the number of beam-related events from the ν e C → e − X inclusive reaction is observed. The excess is too large to be explained by normal ν e contamination in the beam at a confidence level greater than 99%. If interpreted as an oscillation signal, the observed oscillation probability of (2.6 ± 1.3 ± 0.5) × 10 −3 is consistent with the previously reported ν μ → ν e oscillation evidence from LSND.