[time-nuts] Neutrino timing

John Miles jmiles at pop.net
Mon Oct 24 23:43:02 UTC 2011

> Do read the article in question. You would love to see the graphs and
> texts. It's quite readable.
> The SPS produces 400 GeV/c protons which is extracted by a kicker magnet
> in two 10,5 us long bursts, 50 ms apart. See page 4 of 1109.4897v1.
> http://arxiv.org/abs/1109.4897
> Contol is well timed with the Xli GPS receiver.

>From page 7: "It is worth stressing that this measurement does
not rely on the difference between a start (t0) and a stop signal but on 
the comparison of two event time distributions."

I wish I had time to go through the whole paper. :(  One thing that makes me
a bit nervous right off the bat: unless these time distributions are
identical in shape, they will have different phase velocities.  If edge A is
produced by an impulse with different spectral characteristics than those
associated with a second edge B, then you cannot trivially say that edge A
is X nanoseconds ahead of or behind edge B.  Paradoxical "faster-than-light"
communication claims based on this misunderstanding are not unheard-of in
the hallowed halls of Usenet.

But it's unthinkable that phase velocity and group velocity would be
unaccounted-for at this level of play...

-- john

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