Update: It is of course worth recalling that the MINOS experiment also measured the neutrino speed and got a result faster than the speed of light at 1.7 sigma see If the OPERA measurements are consistent with this measurement it will have to be taken seriously. For now we will need to wait for the official seminar at CERN on Friday to see what they have to say about that. The rumoured “6.1 sigma” significance is probably a statistical error and it will be important to consider any systematic sources of error before coming to conclusions. Of course such extraordinary claims need very good evidence and for now the most likely explanation by far is a systematic error. Early attempts to measure the squared mass of the neutrino in the 1990s always seemed to give negative results I have not had time to look back at that old ideas but it may be time to do that. In fact some “crazy” people believed in superluminal neutrinos well before that. Other people just say that the neutrinos were created before the gamma rays. Some people claimed that observations of neutrinos arriving before gamma rays from supernovae implied that they are superluminal see . However this is not the first time that superluminal neutrinos have been reported. You would need a very unconventional variation of relativistic quantum field theory to stop the universe degenerating into an instant burst of neutrinos, and we don’t have that. Aside from the causality issues, the vacuum becomes unstable because you can create neutrino pairs with negative energy out of nothing. Hypothetical superluminal particles are known as tachyons and they always move faster than light because they have imaginary valued mass, but quantum field theories for tachyons have terrible problems. That does not sound very likely (but I am now setting up a neutrino beam to send the news back in time so that it was actually me who leaked the story) . Even if neutrinos are hard to detect it should be possible to use them to send information into the past if this result holds up. This is of course a crazy idea because if true it would violate everything we think we know about causality. The claim now is that they have measured the speed of muon neutrinos and got a result faster than the speed of light!
SUPERLUMINAL TEETH UPDATE
The rumour confirmed that this meeting was rescheduled to Friday but as an update on OPERA, the neutrino experiment which a couple of years ago saw its first tau neutrino. There had been a seminar titled “Seminar DG” which was listed on indico and removed the day before it was due. I reported it in an update on the Seminar Watch post. Four days ago a rumour started circulating in the comments at Resonaances that some “6.1 sigma” signal of new physics had been seen at CERN.