OPERA not contradicted by SN1987a
Everyone is talking about the exciting results from OPERA on the superluminal velocities of neutrinos (arXiv:1109.4897, 23-Sep-2011), which were explained in an excellent CERN EP Seminar given this afternoon. The speaker was Dario Autiero (Institut de Physique Nucleaire de Lyon):
Many people point out that the OPERA result:
δv/c = (2.48 ± 0.28(stat) ± 0.30(syst)) × 10-5,
would seem to be contradicted by constraints coming from Supernove 1987a. viXra quotes this constraint as δv/c < 2 × 10-9 for typical neutrino energies of 10 MeV.
The OPERA analysis was essentially described in a paper by John Ellis, Nicholas Harries, Anselmo Meregaglia, Andre Rubbia, Alexander Sakharov
(arXiv:0805.0253, May 2008) who are motivated by considerations of Quantum Gravity. They consider two scenarios, in which the deviations from c depend linearly or quadratically on the neutrino energy.
Motivated by this idea, and the number quoted on viXra log, I made the following plot. It shows the upper limit on δv/c as a function of the neutrino energy, for the quadratic and the linear assumptions. These limits are drawn as continuous curves (straight lines on a double-log plot). The region above the curve is excluded.
As you can see, the OPERA points are not exluded by the SN1987a limit as cited by viXra log, in the quadratic case. In the linear case, there is apparently a contradiction.
Of course, this does not mean that the OPERA results are right. Only confirmation by an independent experiment, preferably with different metrology techniques, will convince me and everyone else that this astounding result is correct.
Entry filed under: Particle Physics.