Abstract

The OPERA experiment at Gran Sasso was designed to observe the n_m into n_t oscillation in appearance mode, in the parameter region suggested by SuperKamiokande and MINOS results.

The experiment is composed by nuclear emulsions complemented by electronics detectors to locate neutrino interactions in the emulsions and to reduce the background.

The collaboration released during Summer 2011 the complete analysis of the neutrino events collected in 2008 and 2009 runs, among which one tau neutrino has been identified.

The location of 2010 and 2011 events is on-going.

An analysis aimed at the identification in the data of n_m into n _e oscillation has also started for a determination of q₁₃.

Recently we reported about the measurement of the neutrino velocity over the 730 km baseline from CERN to Gran Sasso.

The measurement is based on the data acquired by the electronic detectors of the experiment from 2009 to 2011, when a ns synchronization was achieved between the two laboratories.

The measured value is higher then the light speed, corresponding to an anticipation of about 60 ns, with a significance of about 6 sigmas.