Results on {nu}{sub {mu}}{r_arrow}{nu}{sub e} oscillations from pion decay in flight neutrinos

A search for {nu}{sub {mu}}{r_arrow}{nu}{sub e} oscillations has been conducted at the Los Alamos Meson Physics Facility using {nu}{sub {mu}} from {pi}{sup +} decay in flight. An excess in the number of beam-related events from the {nu}{sub e}C{r_arrow}e{sup {minus}}X inclusive reaction is observed. The excess is too large to be explained by normal {nu}{sub e} contamination in the beam at a confidence level greater than 99{percent}. If interpreted as an oscillation signal, the observed oscillation probability of (2.6{plus_minus}1.0{plus_minus}0.5){times}10{sup {minus}3} is consistent with the previously reported {bar {nu}}{sub {mu}}{r_arrow}{bar {nu}}{sub e} oscillation evidence from LSND. {copyright} {ital 1998} {ital The American Physical Society}