[LEAPSECS] preprint about timekeeping for neutrino experiment
zefram at fysh.org
Thu Sep 29 17:51:23 EDT 2011
Rob Seaman wrote:
>Or maybe a POSIX timestamp?
With a 2.4 ms flight time, it seems unnecessary to track which second
the events occur in. Leap seconds are a non-issue.
When I read about the neutrino result in the media, I was immediately
struck by the diverse and subtle range of relativistic effects that one
would have to account for in order to meaningfully make the measurement,
quite apart from merely synchronising the clocks. Gravitational *space*
dilation is a fairly obvious one, making the path taken by the neutrinos
slightly shorter than one would expect from applying Euclidean geometry
to geodetic measurements made above the Earth's surface. Looking at
the OPERA paper, it's worrying to see that this issue, like many that
the Contaldi paper listed, is not mentioned.
In fact, the OPERA paper makes no mention at all of any relativistic
corrections, even for matters as simple as the labs being at different
altitudes. I saw a quote from one of the researchers along the lines
of "we're clever enough to have ruled out this being a trivial error".
But it's looking rather as though they ignored relativity entirely,
which is a fairly basic error when measuring things near light speed.
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