sci.physics.particle

On Apr 2, 12:12 am, Tom Roberts wrote:
> Darwin123 wrote:
> > [about Hafele and Keating's experiment]
> > There is a less extreme position that the 1971 HK experiment
> > was a test of general relativity. It was a test of GR only so far as
> > SR is part of GR.
>
> This is not "less extreme", this is mainstream -- the H&K experiment can
> only be interpreted as a test of GR, because SR is inadequate to analyze it.
>
> > The experimental conditions were set up so the
> > difference in gravitational potential was entirely negligible.
>
> This is not true at all. For the eastbound trip the predicted
> gravitational effect was 80% of the kinematic effect, and for westbound
> it was 180% -- not "negligible" at all!
>
I am not sure where you got your numbers. Unfortunately, I read
the articles a long time ago so I can't give my references either.
However, Hafele had an calculation article where he broke up his
calculated results into separate components. One article describes the
experiment and compares it to calculation, one article decomposes the
calculation in SR and GR components. There was no doubt that the GR
component was within experimental uncertainty. The difference between
SR calculations and experiment results was within experimental
uncertainty. The HK experiment (east-west) was a confirmation of SR.
I read accompanying articles by Hafele. He gave estimates of the
"special relativity" part of the correction, and the "general
relativity" part of the correction. The general relativity part was
the theoretical correction subtracted from the correction that could
be performed using special relativity alone. The contribution of this
part was almost exactly the same for the clock going east, the clock
going west, and the NBS clock.
For the first experiment, where the airplanes were going either
eatward or westward, the "general relativity" part of the correction
was small. The GR component was nonzero but experimentally negligible.
The experimental results did not depend on the equivalence principle.
It was simple Lorentz time dilation.
A later experiment by someone else did a similar experiment where
the traveling clocks circled the earth in the North and South
directions. In THAT experiment, the SR component was experimentally
negligible while the GR component matched the experimental results
within the uncertainty. You see that in THAT experiment, the radial
acceleration of all three clocks was the same. The only difference
between clocks was the gravitational potential, because the earth is
elongated at the equator. Again, the article broke the results into an
SR and a GR component. Therefore, the experimental results directly
validated the equivalence principle. Lorentz time dilation was not
directly involved.