Evidence for neutrino oscillations from muon decay at rest

A search for <(nu)over bar>(mu)--><(nu)over bar>(e) oscillations has been conducted at the Los Alamos Meson Physics Facility using <(nu)over bar>(mu) from mu(+) decay at rest. The <(nu)over bar>(e) are detected via the reaction <(nu)over bar>(e)p-->e(+)n, correlated with the 2.2 MeV gamma from np-->d gamma. The use of tight cuts to identify e(+) events with correlated gamma rays yields 22 events with e(+) energy between 36 and 60 MeV and only 4.6+/-0.6 background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1X10(-8). A chi(2) fit to the entire e(+) sample results in a total excess of 51.0(-19.5)(+20.2)+/-8.0 events with e(+) energy between 20 and 60 MeV. If attributed to <(nu)over bar>(mu)--><(nu)over bar>(e) oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of (0.31+/-0.12+/-0.05)%.