Speaker
Chiara Sirignano
(PD)
Description
The OPERA experiment : new results.
The OPERA experiment is designed to search for nu_mu->nu_tau oscillations in appearance mode through the direct observation of the tau lepton in nu_tau Charged Current interactions. The nu_tau CC interaction is identified through the detection of the τ lepton decay topology in the so called Emulsion Cloud Chamber (ECC), passive lead plates constituting the target mass interleaved with nuclear emulsion films providing the high spatial resolution. Electronic detectors complement the ECCs.
The experiment recorded data for five years, since 2008, with the CNGS, a quasi-pure nu_mu beam from CERN to the Gran Sasso laboratory LNGS, collecting 1.8 ×1020 protons on target. The running of the detector and the data collection from the emulsions films by means of fast automatic optical microscopes will be described, together with the special procedures used to locate the interactions vertices and to detect short decay topologies. OPERA has also good capabilities in detecting electron neutrino interactions and can set limits on the nu_mu->nu_e oscillation channel. Since last year, a large amount of additional data has been analyzed. The latest results on oscillations with the increased statistics, including the fourth tau neutrino candidate event, will be presented.
Primary author
Chiara Sirignano
(PD)
