Improved limits on oscillation parameters from νe-disappearance measurements at the Gösgen power reactor

Abstract The positron spectrum from the reaction ν e + p → e + +n was measured at a distance of 64.7 m from the core of the Gosg en power reactor. These new data, combined with those of previous measurements performed under otherwise identical conditions at 37.9 m and 45.9 m, were analyzed in terms of two-neutrino oscillations of the type ν e ↔ x . No evidence for neutrino-oscillations was found. In particular, the oscillation parameter region favored by an experiment at the Bugey reactor is not supported by the data presented here.