I gave another talk on the OPERA ‘faster-than-light’ neutrino experiment on Wednesday evening at University College Cork (UCC). I was booked months ago to give the talk as part of the UCC Public Lecture Series and it’s always a pleasure to visit the beautiful campus at UCC.
University College Cork – the nicest campus in Ireland?
Of course, I was concerned the topic might be a bit of damp squib. As everyone in physics knows, a technical fault associated with the OPERA experiment was recently uncovered. Specifically, a connector cable for GPS clock synchronisation was found to be faulty. Between this and other problems, the ‘faster-than-light’ result has been withdrawn (see here for details).
The neutrino detector at Gran Sasso
In fact, the lecture was great fun. We got a good turnout and I made a point of using exactly the same slides I used when the OPERA result was first announced (see here for details). I thought the parts of the talk where I explained the grounds for scepticism from the viewpoint of both special and general relativity (theory and experiment) looked well in retrospect, though I tried hard not to say We told you so. In conclusion, I introduced a few new slides where I discussed what lessons could be learnt from the incident e.g.
1. If your result is in conflict with well-known theory, check, check and check again before you publish (anywhere).
2. If your result is in conflict with decades of experiments, check even more carefully.
3. Never underestimate the media appetite for ‘Einstein wrong’ stories. Everyone has heard of Einstein and everyone has heard of the speed of light – this story was always going to be huge.
4. ‘Einstein not wrong after all’ is not such a great media story. In consequence, many members of the public will never get to hear of the correction. Bear this in mind before you go public with a result that may later have to be corrected.
Check your cables – all of them!
The slides I used for the UCC talk are here and I will upload the video in a day or two.
This just in: a group working on an extremely similar neutrino experiment at Gran Sasso have announced the observation of neutrinos obeying the speed limit, as normal. This pretty much refutes the OPERA result completely. See here for details.
April 3: The head of the OPERA collaboration has resigned over the weekend, see here for details