Friday, November 18, 2011

OPERA Still Sees Superluminal Neutrinos

Well, they did a check, and they continue to insist that they see these superluminal neutrinos.

The new tests, completed 6 November, did away with the statistical analysis by splitting each pulse into bunches just 1- to 2-nanoseconds long, allowing each neutrino detected at Gran Sasso to be tied to a particular bunch produced at CERN. These tests were carried out over 10 days and provided 20 events. The researchers confirmed that the neutrinos arrived 60 nanoseconds early, with an uncertainty of about 10 nanoseconds, comparable to that of the initial result.
What they had done is to see if the bunch length could be the source of the error. I think most people that I talked to think it is more of a timing/analysis error, which they haven't really looked into yet.

You may read the updated preprint of the OPERA paper here, which includes this latest short-bunch test.

A major concern among the dissenters is the fact that the "time window" within which neutrinos were detected by OPERA in the most recent run had a width of 50 nanoseconds, something that the leader of the superluminal analysis, Dario Autiero, only revealed once the tests had been carried out. It was initially assumed that this window was just 10 nanoseconds wide. This difference does not affect the final result itself, the source notes, but dissenters say it highlights poor experimental procedure. Some researchers are also unhappy that only a small fraction of the analysis, which was carried out by Autiero, has been independently checked by others within the collaboration. This leaves open the possibility, they say, that not all possible errors have been accounted for.
It will be interesting to see what happens during the referring process. I can certainly see this being published, but with a result this important and this controversial, the only way it will ever be accepted is if T2K and MINOS verify the result. It is as simple as that.


1 comment:

Bruno said...

Sorry, I'm not a physic.
I'm an engineer though; and I was thinking about this superluminal neutrinos... and I was wondering: how good is our estimation of the speed of light? Is it possible we simply understimated it? Maybe the neutrinos' speed is just a more accurate estimation of the speed of light, isn't it possible?
No polemics please, I'm just asking for an explanation