Search for anomalies in the [ny]e appearance from a [ny][mi] beam

Abstract

We report an updated result from the ICARUS experiment on the search for ν μ →ν e anomalies with the CNGS beam, produced at CERN with an average energy of 20 GeV and traveling 730 km to the Gran Sasso Laboratory. The present analysis is based on a total sample of 1995 events of CNGS neutrino interactions, which corresponds to an almost doubled sample with respect to the previously published result. Four clear ν e events have been visually identified over the full sample, compared with an expectation of 6.4±0.9 events from conventional sources. The result is compatible with the absence of additional anomalous contributions. At 90 % and 99 % confidence levels, the limits to possible oscillated events are 3.7 and 8.3 respectively. The corresponding limit to oscillation probability becomes consequently 3.4×10 -3 and 7.6×10 -3 , respectively. The present result confirms, with an improved sensitivity, the early result already published by the ICARUS Collaboration.