Search for $\nu_\mu\rightarrow\nu_\tau$ oscillation with the OPERA experiment in the CNGS beam

TL;DR

The OPERA experiment aims to detect $ u_ au$ appearance from $ u_0$ oscillations over a 730 km baseline, reporting initial candidate events and analyzing early data to assess statistical significance.

Contribution

This paper reports the first candidate $ u_ au$ event in the OPERA experiment and evaluates the significance of this observation based on early data from 2008-2009.

Findings

First $ u_ au$ candidate observed in OPERA

Analysis of early data shows initial evidence of $ u_ au$ appearance

Statistical significance of the event is assessed

Abstract

The OPERA neutrino experiment in the underground Gran Sasso Laboratory (LNGS) was designed to perform the first detection of neutrino oscillations in direct appearance mode in the $\nu_\mu\rightarrow\nu_\tau$ channel, the $\nu_\tau$ signature being the identification of the $\tau$-lepton created in its charged current interaction. The hybrid apparatus consists of a large mass emulsion film/lead target complemented by electronic detectors. It is placed in the high energy long-baseline CERN to LNGS neutrino beam (CNGS) 730 km away from the neutrino source. The observation of a first $\nu_\tau$ candidate event was reported in 2010. In this paper, we present the status of the experiment based on the analysis of the data taken during the first two years of operation (2008-2009). The statistical significance of the one event observed so far is then assessed.