Neutrinos faster than light

In September 2011, the OPERA experiment announced to have measured the travel time of the neutrinos between their production at the output of the CERN SPS and their arrival in the OPERA detector in Gran Sasso tunnel 730 km away [Ada11]. The precision of the measurement, based on the use of a GPS signal, was sufficient to claim that neutrinos could have traveled faster than the speed of light in vacuum c. This result was in contradiction with a fundamental law from the Theory of Relativity which excludes any propagation of energy or matter faster than c (Einstein is wrong!). It trigerred a lot of articles in the press and shows in TV, as well as theoretical papers on one side and experimental verifications on the other side (Borexino, ICARUS and LVD, observing the CNGS beam at the same place as OPERA at the Gran Sasso) .

After months of investigations, the OPERA team finally found that its result was biased by an optical  fiber attached improperly and a clock oscillator ticking too fast at the level of the GPS receiver [Ada12]. At the same time, Borexino [Alv12], ICARUS [Ant12] and LVD [Aga12] did not confirm that neutrinos would travel faster than light. The anomaly was definitively killed at the Neutrino-2012 Conference in Kyoto [Ber12].

An interesting point of view (studies of the OPERA anomaly that could be relevant for analyses from the perspective of phenomenology of philosophy of science) is given in [Ame12].

More details can be found in


Ada11T. Adam et al., OPERA CollaborationMeasurement of the neutrino velocity with the OPERA detector in the CNGS beamarXiv:1109.4897v1
Ada12T. Adam et al., OPERA CollaborationMeasurement of the neutrino velocity with the OPERA detector in the CNGS beamJHEP 10 (2012) 093; arXiv:1109.4897v4
Aga12N. Yu. Agafonova et al., LVD collaborationDetermination of a time shift in the OPERA set-up using high energy horizontal muons in the LVD and OPERA detectorPhys. Rev. Lett. 109 (2012) 070801; arXiv:1206.2488
Alv12P. Alvarez Sanchez et al., Borexino collaborationMeasurement of CNGS muon-neutrino speed with BorexinoPhys. Lett. B716 (2012) 401; arXiv:1206.3554
Ame12G. Amelino-CameliaPhenomenology of philosophy of science: OPERA dataarXiv:1206.3554
Ant12M. Antonello et al., ICARUS collaborationPrecision measurement of the neutrino velocity with the ICARUS detector in the CNGS beamJHEP 11 (2012) 49; arXiv:1208.2629
Ber12S. BertolucciNeutrino speed: a report on the muon-neutrino speed measurements of the Borexino, ICARUS and LVD experiments with the CNGS beamNucl. Phys. B (Proc. Suppl.) 235-236 (2013) 289