The time that has elapsed since the seminar held at CERN on September 23, when the collaboration released its first results on neutrino velocity, has been used to verify the main aspects of data analysis and, above all, to carry out new tests. with the neutrino beam established by CERN. This new beam is characterized by having packets of particles of about 3 nanoseconds in duration separated by up to 524 nanoseconds. In this way, compared to the previous measurement,the neutrino beams detected by OPERA are narrower and more widely spaced. This allows a more precise measurement of its speed at the cost of obtaining a lower intensity of the beam: only 20 neutrino events have been collected by OPERA in this new test, compared to the 15,000 analyzed in the previous measurement.
“Such a delicate measure that carries such profound implications in physics requires extraordinary control”, assured Fernando Ferroni, president of the Italian Institute of Nuclear Physics (INFN), which operates the Gran Sasso laboratory. “The OPERA experiment, thanks to a specially adapted neutrino beam from CERN, has made an important test of the consistency of its results.” The positive test result makes us more confident, althoughanalogous measurements will have the last word in other experiments.
“One of the possible systematic errors is ruled out, but the search is not over. There are more tests of systematic errors under discussion, one of them could be to take a time synchronization reference at CERN and Gran Sasso independently of GPS, possibly using a fiber ?, added Jacques Martino, director of the National Institute of Nuclear and Particle Physics (IN2P3) of the French CNRS.
