Thursday, September 22, 2011 

There’s been an interesting newskkake and premature twittergasm of commentary on the pre-publication announcement of results from an experiment at CERN that suggest that neutrinos traveled from CERN to Italy faster than the speed of light.

The announcement reminds me a bit of absolutely unbreakable quantum cryptographic key distribution where the theory was strong but weaknesses in any real detector make Eve’s job easier than theory would suggest.

As the CERN paper was published in the last few hours atarxiv.org none of the reporters who’s breathless reports are generating so many tweets actually read the paper they are reporting on. Remember what happened when UT issued a press release before the paper was peer reviewed.

The conclusion of the paper is that the experimenters measured a time of flight discrepancy of 60.7 +/- 14.3ns or 0.00248% +/-.00058% [(v-c)/c%]. If one reads the paper, the complexity of measuring time of flight over 730km to a nanosecond or two isn’t trivial and there’s a huge number of very complicated (but very accurate) measurements between Switzerland and Italy that go into computing this result, it isn’t like you can just call up and fire a neutrino and say “let me know when you see it.”

The CERN measurement isn’t that far off the 2007 MINOS measurement of 0.0051% +/- .0029% (v-c)/c%. The MINOS experiment wasn’t hyped, but it does tend to validate the CERN experiments (or, more accurately, vice versa).Opera_C_plus.jpg

It is important to remember that the six sigma of the 10x more accurate CERN measurement (than MINOS) is about 2 parts per billion, not far off the odds of winning a multi-state lottery. That is, chances are 50/50 that if you had 500 million researchers testing fundamental constants to equal accuracy, you’d get an anomalous result like this overturning some branch of physics every publication cycle that would turn out to be erroneous. And this is why scientists don’t start rewriting textbooks on the first anomalous result, even if breathless journalists try to.

Further, it is also important to note that the researchers do not speculate that the neutrinos are actually traveling faster than light in violation of general relativity, even if the experiments can be repeated, rather that Leonard has created a little more work for Sheldon. Both “traditional” relativistic phenomenon and poly-dimensional theories (like string theory) provide a theoretical framework whereby in our observation frame an object moving in a different reference frame might appear to be moving faster than the speed of light in our reference frame, for example, perhaps neutrinos interacting oddly with gravitational time dilation. Or, maybe, just maybe, there’s room in the universe for a 0.0051% error: good enough for government work. Or maybe, as Newtonian mechanics described life at human velocities accurately but failed to describe relativistic phenomenon, so too relativity may not be a complete description of the universe.


Posted at 21:34:23 UTC

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