In the 70's, as small team on th SLAC facitilites took some opportunities (1) to check an replacement theory for special relativity, called "autodynamics" (2).
The paper (1) relating their results might no be totally understandable for readers unfamiliar with particle accelerator technologies.
Also, the goal of checkin "Autodynamics" is probably not familiar to most people.
However the salient feature are no so complicated.
Here are the main parts of this experimental setup:

• An electron accelerator.
  
• A "momentum slit" that filters particles according to their momentum.
  It is based (I think) on the deviation of charged particle in a magnetic field.
  The particles are selected according to their momentum because the deviation depends on two parameters:
  - the gyroradius R = P/e.B where P is the momentum of the electron, e its charge, B the magnetic field
  - the length of the device
  
• An ampmeter to measure the beam current
  
• A beam dump calorimeter to measure the power of the beam (kinetic energy)

Such a measurement might not have a very good precision because of the calorimetric part of it.
However, if two theories disagree widely on the outcome, the precision might not be an issue.
This is what happens when comparing SR to autodynamics.

Therefore, I have no the following question:

Can the results in (1) also be used to discrimates Special relativity (SR) from Galilean relativity (GaR).
There are two aspects, I think, to be considered:

- the momentum selected by the "momentum slit" will be interpreted diffently by SR or GaR.
- the energy-momentum relation is different in SR and GaR.

And of course, is SR or GaR confirmed by this experiment?

(insight from accelerator specialists welcome)

(1) http://www.slac.stanford.edu/pubs/slacpubs/2000/slac-pub-2890.html
(2) http://en.wikipedia.org/wiki/Autodynamics

The gyroradius is given by the same expression R=p/e.B in both classical and relativistic mechanics.
Therefore a classical physicist and a relativistic physicist would agree on the selected momentum.

However, the classical physicist will use the classical formula Kc=p²/2m for the kinetic energy,
while the relativistic physicist will use the relations E²=p²c²+(mc²)² and Kr=E-mc².

Calculating the ratio between the classical result and the relativistic result leads to:

Kc/Kr = (Sqrt(1+x²)+1)/2

where

x = pc/(mc²)

For a 20GeV/c electron beam, the parameter x = 20GeV/511keV = 39000
and therefore, Kc/Kr = 19570 .

Conclusion

For electrons with a momentum of 20GeV/c, the SLAC beam has a typical power of 100kW measured by calorimetry.
These calorimetric measurements (1) are within 30% in agrement with the relativistic calculations.
In contrast, the power predicted by the classical theory would be 19570 times higher.

In other words, when designing the SLAG, the classical engineers would have assumed a beam power of 2 GW instead of 100 kW !

This simple experiment (1) is indeed supporting special relativity, despite the poor precision of the calorimetric measurements.


(1) http://www.slac.stanford.edu/pubs/slacpubs/2000/slac-pub-2890.html

Re: Lal, This experience strongly discriminates between SR and GalileanR March 6 2009, 4:44 PM

Lal,
"These calorimetric measurements (1) are within 30% in agrement with the relativistic calculations.
In contrast, the power predicted by the classical theory would be 19570 times higher."

How about a little truth in reporting lal. You are giving a % ratio (30%) for the relativistic comparison and a multiple ratio (19570) for the classic theory comparison. Either use the % ratio for both or the multiple ratio for both because I don't read in the conclusion where it states "19570 times higher".