Time-of-flight Measurements
In September 2011, OPERA researchers observed muon neutrinos apparently traveling faster than the speed of light. In February and March 2012, OPERA researchers blamed this result on a loose fibre optic cable connecting a GPS receiver to an electronic card in a computer. On 16 March 2012, a report announced that an independent experiment in the same laboratory, also using the CNGS neutrino beam, but this time the ICARUS detector, found no discernible difference between the speed of a neutrino and the speed of light. In May 2012, the Gran Sasso experiments BOREXINO, ICARUS, LVD and OPERA all measured neutrino velocity with a short-pulsed beam, and obtained agreement with the speed of light, showing that the original OPERA result was mistaken. Finally in July 2012, the OPERA collaboration updated their results. After the instrumental effects mentioned above were taken into account, it was shown that the speed of neutrinos is consistent with the speed of light. This was confirmed by a new, improved set of measurements in May 2012.
Read more about this topic: OPERA Experiment