  A search for nu_bar_mu to nu_bar_e oscillations has been conducted at the Los
Alamos Meson Physics Facility using nu_bar_mu from mu+ decay at rest. The
nu_bar_e are detected via the reaction (nu_bar_e,p) -> (e+,n), correlated with
the 2.2 MeV gamma from (n,p) -> (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 4.1E-08. A chi^2 fit to
the entire e+ sample results in a total excess of 51.8 (+18.7) (-16.9) (+/-
8.0) events with e+ energy between 20 and 60 MeV. If attributed to nu_bar_mu ->
nu_bar_e oscillations, this corresponds to an oscillation probability (averaged
over the experimental energy and spatial acceptance) of 0.0031 (+0.0011)
(-0.0010) (+/- 0.0005).
