The major achievements of the OPERA experiment and its legacy

Abstract

The OPERA experiment was designed to discover the [Formula: see text] appearance in a pure [Formula: see text] beam, resulting from neutrino oscillations. The detector, located in the underground Gran Sasso Laboratory, consisted of an emulsion/lead target complemented by electronic detectors and was exposed, from 2008 to 2012, to the (CERN Neutrinos to Gran Sasso (CNGS)) beam, an almost pure [Formula: see text] beam with a baseline of 730 km, collecting a total of [Formula: see text] protons on target. OPERA was unique in its capability of detecting all three neutrino flavors. OPERA discovered [Formula: see text] oscillations in appearance mode with a significance of [Formula: see text]. In this review, we report the major achievements of the OPERA experiment and its legacy in the nuclear emulsion technology.