Physical Dimensions

Poll 90 - "With which statement do you agree? Scientific experiments demonstrating that neutrinos traveled faster than light will: 1) require a re-writing of the laws of physics. 2) eventually be shown to be a measurement error, no faster-than-light travel occurred." Poll ended February 10, 2012. 58.6% chose option one, while the remaining 41.4% picked the second answer.

Speaking personally, I fall in the camp of people who suspect that these faster-than-light indications will eventually be shown to be the result of some sort of measurement error. Nonetheless, I have to suggest that if this faster-than-light evidence were eventually confirmed without a doubt, I believe that rather than requiring a re-write of the existing laws of physics (and more specifically Einstein's special theory of relativity), this would finally be a confirmation of the existence of extra dimensions: the conclusion we should reach is that these neutrinos were somehow using the "fold" of the next dimension up to arrive at their destination just a tiny bit sooner than Einstein's "speed of light" limit allows.

How much are we talking about when we say a tiny bit here? In the European experiment called OPERA (Oscillation Project with Emulsion-Tracking Apparatus), these neutrinos appear to have traveled from CERN in Geneva to an underground lab in Italy 60 billionths of a second faster than the speed of light would allow! Such a miniscule amount, but still amazing if it were true.

Since it's now over five months since this evidence was first presented, let's look at some of the most recent musings about what this all could mean. First of all, here's a recent article interviewing Lyn Evans, the former director of the LHC,  in which he discusses the results of the OPERA experiment. Lyn says this:

I’m working on an independent experiment that should start in a few months and we should have the results by the end of summer. If that gives the same result then we start to worry about extra dimensions.

So Lyn would appear to be in agreement with my thoughts on this topic. But he's certainly not the only scientist interested in trying to confirm or refute the evidence of these extra-speedy neutrinos. A recent Scientific American blog entry writes about experiments being planned at the Fermilab facility in Batavia, Illinois:

Fermilab has its own cutting-edge neutrino experiment that should be able to confirm or (as most suspect) refute the OPERA claim—as well as probe other puzzles of these particles. MINOS (Main Injector Neutrino Oscillation Search) shoots a beam of neutrinos through two detectors, one at Fermilab and one in a Minnesota mine some 735 kilometers away... A planned project called NOvA will succeed MINOS, extending the baseline of the neutrino experiment to about 800 kilometers and adding a much larger detector on the Minnesota end.

The scientists responsible for the first test have already repeated their experiment and found the same small but significant faster-than-light evidence, as reported in this arxiv.org submission. In fact, there were some scientists who participated in the first experiment but were not willing to have their names attached to the results. But because the second experiment was conducted in an even more stringent setup to help reject some possible sources of measurement errors,  most of those scientists were now willing to have their names added to the second paper, after this more refined experiment was unable to disprove the existence of these faster-than-light-speed neutrinos.

The controversy continues. As reported in this article from the November 2011 Wired:

Tommaso Dorigo, a physicist at CERN, noted on his blog that there are still other possible sources of error. For instance, the OPERA collaboration’s clock might not have a fine enough resolution to determine exactly when the neutrinos arrived. “The measurement therefore is only a ‘partial’ confirmation of the earlier result: It is consistent with it, but could be just as wrong as the other,” he wrote.
Ultimately, the only thing that would convince many in the field is if another team upholds the findings in an independent experiment. Plunkett, co-spokesperson for the Main Injector Neutrino Oscillation Search (MINOS) experiment at Fermilab, says that his collaboration expects to have results checking the OPERA findings in the spring of 2012.

Today, just as I was about to publish this entry, I see that there is a new buzz that it was a faulty connection on a GPS cable which caused the observed measurement error. Here's a link to the update from New Scientist:
http://www.newscientist.com/blogs/shortsharpscience/2012/02/speedy-neutrino-result-may-be.html
In this article you'll see that CERN is already planning confirmation tests for May, and that the OPERA team plan to release an update to their position on this controversy tomorrow. Needless to say, I'm keeping my eye on this one!

Enjoy the journey,

Rob Bryanton

Update: Here's a very interesting article published by Physics Today which discusses the original carefully worded news release showing that there are two factors being called into question, one of which would have have magnified the faster-than-light result, and one of which would have diminished it, and hence the need for more tests to be run in May. The article shows how most mainstream science news reports spun this information into articles, and in particular headlines, which had been crafted to give the impression that these scientists were already saying they had found an error which disproved the faster-than-light result, and that's simply not the case. So patience everyone, let's find out what's really happening here before we jump to one conclusion or the other!




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