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Re: Length Contraction

On Fri, 15 Dec 2000, Ludwik Kowalski wrote:

Jack Uretsky wrote:

Hi all-
Leigh's response emphasizes the point that <within the logical
framework of special relativity> length contraction implies time dilation
and vice-versa. This equivalence is evident in the Lorentz
transformations of space and time.
It is nevertheless a fair question, in my opinion, to ask for
independent experimental verification of both predictions.
The only experimental verification of length contraction, of which
I'm aware, comes from the indirect measurements of the interaction regions
in collisions of heavy nuclei at Cern and elsewhere. Those data can be
interpreted to show "flattening of the nuclei" along the collision axis.

Was this an experiment specifically designed to independently
observe the length contraction?
No. Such experiments are designed to investigate the physics
of dense clouds of nuclear matter (pions, kaons, antinucleons, etc.) at
high temperatures (like 200 MeV). (Spin doctors like to describe it
as "recreating conditions in the early universe").

How did they measure the
"interaction regions"?
They used the Hanbury-Brown Twiss effect.

A collision must must be very peripheral to preserve the target
nucleus. How did researchers know, WITHOUT LEANING
ON SPECIAL RELATIVITY, that target nuclei flatten in the
frame of projectiles?

Who said they did? Please reread my carefully worded
posting. For further information see Eur. Phys. J. C2,661, 670 (1998),
and PRL 78(1997)2080. Both are experimental papers.

Can flattening be deduced from the analysis
of the Coulomb scattering cross sections? Probably not.
Ludwik Kowalski
Correct.


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