Faster than light neutrinos, an optical illusion?

by Ramy Brustein (Ben Gurion)

Friday 3 Feb 2012, 14:00 → 15:00 Europe/Berlin

3344 (Physikdepartment)

The OPERA experiment has recently reported that neutrinos propagating through Earth from CERN to Gran Sasso arrive earlier than if they were propagating at the speed of light in vacuum. This measurement has attracted the attention of scientists as well as the general public. I will first review the measurement and the extensive attempts to find some errors in it. Assuming that the measured time shift is indeed related to the propagation of neutrinos, I will argue that it is likely not a measurement of Lorentz invariance violation, since Lorentz symmetry is highly constrained in the neutrino sector. Then I will argue that the effect has to be both a matter effect and a collective effect. I will end by discussing our scenario that the index of refraction of the neutrino wave in rock is smaller than unity. This framework can be used to explain the measured time shift and to predict the results of additional experiments, so it can be verified in the near future.