Improved search for muon-neutrino to electron-neutrino oscillations in MINOS

We report the results of a search for e appearance in a beam in the MINOS long-baseline neutrino experiment. With an improved analysis and an increased exposure of 8.2 1020 pro- tons on the NuMI target at Fermilab, we find that 2sin2(23)sin2(213) < 0.12 (0.20) at 90% confidence level for =0 and the normal (inverted) neutrino mass hierarchy, with a best fit of 2sin2(23)sin2(213)=0.041+0.047 (0.079+0.071). The 13=0 hypothesis is disfavored by the MINOS 0.031 0.053 data at the 89% confidence level.