OPERA Confirms: Neutrinos Travel Faster Than Light

XiXiDu

New high-precision tests carried out by the OPERA collaboration in Italy broadly confirm its claim, made in September, to have detected neutrinos travelling at faster than the speed of light. The collaboration today submitted its results to a journal, but some members continue to insist that further checks are needed before the result can be considered sound.

Link: nextbigfuture.com/2011/11/faster-than-light-neutrinos-opera.html

The OPERA Collaboration sent to the Cornell Arxiv an updated version of their preprint today, where they summarize the results of their analysis, expanded with additional statistical tests, and including the check performed with 20 additional neutrino interactions they collected in the last few weeks. These few extra timing measurements crucially allow the ruling out of some potential unaccounted sources of systematic uncertainty, notably ones connected to the knowledge of the proton spill time distribution.

[...]

So what does OPERA find ? Their main result, based on the 15,233 neutrino interactions collected in three years of data taking, is unchanged from the September result. The most interesting part of the new publication is instead that the find that the 20 new neutrino events (where neutrino speeds are individually measured, as opposed to the combined measurement done with the three-year data published in September) confirm the earlier result: the arrival times appear to occur about 60 nanoseconds before they are expected.

Link: science20.com/quantum_diaries_survivor/opera_confirms_neutrinos_travel_faster_light-84763

Paper: kruel.co/paper-neutrino-velocity-JHEP.pdf

Previously on LW: lesswrong.com/lw/7rc/particles_break_lightspeed_limit/

New high-precision tests carried out by the OPERA collaboration in Italy broadly confirm its claim, made in September, to have detected neutrinos travelling at faster than the speed of light. The collaboration today submitted its results to a journal, but some members continue to insist that further checks are needed before the result can be considered sound.

Link: nextbigfuture.com/2011/11/faster-than-light-neutrinos-opera.html

The OPERA Collaboration sent to the Cornell Arxiv an updated version of their preprint today, where they summarize the results of their analysis, expanded with additional statistical tests, and including the check performed with 20 additional neutrino interactions they collected in the last few weeks. These few extra timing measurements crucially allow the ruling out of some potential unaccounted sources of systematic uncertainty, notably ones connected to the knowledge of the proton spill time distribution.

[...]

So what does OPERA find ? Their main result, based on the 15,233 neutrino interactions collected in three years of data taking, is unchanged from the September result. The most interesting part of the new publication is instead that the find that the 20 new neutrino events (where neutrino speeds are individually measured, as opposed to the combined measurement done with the three-year data published in September) confirm the earlier result: the arrival times appear to occur about 60 nanoseconds before they are expected.

Link: science20.com/quantum_diaries_survivor/opera_confirms_neutrinos_travel_faster_light-84763

Paper: kruel.co/paper-neutrino-velocity-JHEP.pdf

Previously on LW: lesswrong.com/lw/7rc/particles_break_lightspeed_limit/

I was thinking about this earlier today, having read/posted about the original findings and the first papers of "Here are all the ways that the original findings might be incorrect.", and then this announcement this morning.

For simplicity, let's assume someone's initial probabilities are:

There is a 1% chance they were correct.

There is an 11% chance they made a Type A error.

There is an 11% chance they made a Type B error.

There is an 11% chance they made a Type C error.

There is an 11% chance they made a Type D error.

There is an 11% chance they made a Type E error.

There is an 11% chance they made a Type F error.

There is an 11% chance they made a Type G error.

There is an 11% chance they made a Type H error.

There is an 11% chance they made a Type I error.

This paper establishes that there is essentially a negligible chance they made a Type A error. But there are still 8 ways they could be wrong. If I'm doing the calculations correctly, this means they now have about a 1.12% chance of being correct from the perspective of that someone, because these findings also mean it is more likely that they made a Type B-I error as well.

This is a gross simplification of the problem. There are other certainly other possibilities than "Correct" and "9 equally likely types of error." But I think this helped me put the size of the task of proving the neutrinos did go faster than light into a better perspective.

This is (minus the specific numbers, of course, but you too were using them as examples) exactly how I see it.

The most likely error - that of wrong baseline - has not been addressed, so I don't have noticeably improved credence. This is a very small update.

5MileyCyrus15y

Are you willing to make a 1:89 bet that they will eventually be proven incorrect?

6JoshuaZ15y

I don't think this is an accurate assessment. One of the most obvious error forms was a statistical error (since they were using long neutrino pulses and then using careful statistics to get their average arrival time). That is eliminated in this experiment. Another possible error was that detection of a neutrino could interfere with the chances of detecting other neutrinos which could distort the actual v. observed average (this is a known problem with some muon detector designs). This seemed unlikely, but is also eliminated by the short pulses. They also used this as an opportunity to deal with some other timing issues. Overall, a lot of possible error sources have now been dealt with.