The OPERA experiment is searching for νμ ν τ oscillations in appearance mode, i.e., via the direct detection of \tau leptons in \nu -\tau charged-current interactions. The evidence of \nu -\mu \rightarrow \nu -\tau appearance has been previously reported with three \nu -\tau candidate events using a sub-sample of data from the 2008-2012 runs. We report here a fourth \nu -\tau candidate event, with the \tau decaying into a hadron, found after adding the 2012 run events without any muon in the final state to the data sample. Given the number of analyzed events and the low background, \nu -\mu \rightarrow \nu -\tau oscillations are established with a significance of 4.2\sigma.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)