# Reproducing the OPERA result

Are there any other facilities that would be capable of independantly verifying the opera result? In other words, a completely different source/detector for $\nu_{\mu}$ beams?

Alternatively, there might be another source that could send a beam to the same detector at Gran Sasso, with a different baseline, looking to verify the value of $\frac {v-c}{c}$ with a different value of $\delta t$?

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• T2K is running right now. They might (probably) need to improve their understanding of the distance and timing.
• LBNE is still in the planning stages, but will have a longer baseline which could be very helpful

disclaimer: I am vaguely involved in LBNE--specifically doing MC work for the near detector design.

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The original observation of neutrinos exceeding the speed of light was by MINOS in 2007. What OPERA did was to verify this observation, with better statistics. These two experiments were the US and Europe, respectively, and have enough differences that it appears that they can be considered as independent.

If this were not a complete earthquake for the special theory of relativity, it would be accepted as a recent observational fact about neutrinos (and largely ignored). The reason it's getting so much attention is because it IS a verification.

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sorry, can you be more specific? what part of that paper is actually saying anything about neutrino speed being above c? it only mentions |v-c|/c – lurscher Sep 26 '11 at 17:42
@lurscher: No absolute value there, and they quote their $\delta t$ as negative. The reason it wasn't a huge circus like the OPERA number is that their error bars were big, so it is only a 1.8$\sigma$ result. – dmckee Sep 26 '11 at 17:56
@Carl Brannen I think the scepticism comes from the multitude of systematics entering in the calculations, and the esoteric way of calculating the final times. It is not a straight forward experiment of measuring the velocity of light in vacuum and the velocity of neutrinos in vacuum ( though admittedly the rock is as vacuum for the weekly interacting neutrinos). There is great trust in the GPS measurements, and as I have commented elsewhere, it is quite possible that the meter has been redefined by the GPS, as it does not operate in vacuum. The difference between accuracy and precision. – anna v Sep 26 '11 at 19:16
@anna v; I think the skepticism comes only from its surprising character. Extraordinary claims require extraordinary proof. The skepticism is appropriate; though it has met many surprising discoveries in elementary particles it has also met many more erroneous experimental results. The way to bet is on the status quo. In this case, the experiment is a verification of a previous (much much weaker) result. Should be entertaining. – Carl Brannen Sep 26 '11 at 20:51
@Ron; If you look at the statistics, you'll realize that they've been several standard deviations away from c since a few months into the experiment (which started in 2009). So they've been sitting on the anomaly since they precisely measured the distance in 2010. – Carl Brannen Sep 28 '11 at 4:32