  We propose to study of the light speed isotropy and Lorentz invariance at
Jefferson Laboratory by means of the measurements of the Compton Edge using of
the Hall A/C existing experimental setup. Methodologically the same experiment
has already been successfully elaborated at GRAAL experiment at the European
Synchrotron Radiation Facility in Grenoble with 6 GeV electron beam. This
Proposal states two goals expected to be reached at Jefferson Laboratory, both
on Lorentz invariance: (a) the one-way light speed isotropy testing accuracy,
following from conservative evaluations at numerical simulations, to about an
order of magnitude better than was GRAAL's; (b) the dependence of the light
speed on the velocity of the apparatus (Kennedy-Thorndike measurement) will be
traced to an accuracy about 3 orders of magnitudes better than the available
limits.
