[time-nuts] Neutrino Velocity Results

[Marvin Marshak]

Good morning,

The "Neutrino Velocity" session at Neutrino 2012 in Kyoto, Japan, is now finished. Six experiments now report no measurable difference between the velocity of neutrinos and the velocity of light. 

The first talk was from the OPERA Experiment at the Gran Sasso Laboratory, the experiment that originally reported superluminal neutrinos last Fall. The OPERA speaker described the previously announced problems with the experiment--a loose fiber optic connection and a 10 MHz oscillator that ran at a slightly incorrect frequency. These two effects together cancel the faster than the speed of light result. He then went on to describe new data collected in May 2012. These results show that the propagation time for neutrinos and light for the CERN-Gran Sasso beam differ by less than the measurement uncertainty of about 5 ns.

The second speaker reported results for three other Gran Sasso experiments--LVD, Borexino and ICARUS. All three also reported differences in propagation times for neutrinos and light smaller than measurement uncertainties, which ranged from 3 to 5 ns.

The third speaker reported results from the T2K (Japanese) and MINOS (U.S.) experiments. Again, propagation time differences are smaller than measurement uncertainties. The uncertainties for these data are in the 20 to 30 ns range, although both collaborations are working on new measurements with expected uncertainties of 1 to 2 ns.

Einstein can rest peacefully.

Best regards,

Marvin


Marvin L. Marshak
College of Science and Engineering Professor
Morse-Alumni Professor
University of Minnesota
116 Church Street SE
Minneapolis MN 55455  612-624-1312     612-624-4578 (fax)