Experimental verification of the deflection angle of massive relativistic particles regarding GR General Relativity (GR) predicts a gravitational deflection angle of light which is twice what Newtonian gravitational acceleration predicts. This "doubled" angle was experimentally verified.
GR also predicts that massive relativistic particles moving close to the speed of light are bent by the same "twice the non-relativistic Newton angle". Was this ever directly experimentally verified ?

Remark 1 : According to this paper, "the effect of gravity on relativistic massive particles was never studied experimentally".
Remark 2 : According to this link, "The orbits of protons in the (LHC) have to be adjusted regularly to account for the gravitational effect of the moon.". I don't know how true this story is. But, if true, maybe the moon could be used to test "the" equivalence principle at a relativistic quantum level.
 A: In this article the effect of tidal earth movements on the LHC beam is discussed:

Geological movements like Earth  tides may change  the  circumference  by  up to 1 mm  with 12 hours . Due to the limited accuracy  of the tidal prediction (at level of a few percent) and to the presence of other slow ground movements, it is not possible to accurately predict changes to $C_c$ to better than $≈0.1 mm$.

It is in page 6 of an esoteric document , and I am quoting it to show that accuracies of microns are hard, and lead to this article, discussing  neutral beams, where the effect of electromagnetic interactions is minimized:

According  to  (3.6),  in  order  to  focus  a  neutral  beam  into  a  1  m  radius  at 1000 km, one would, for example, need a beam with an initial radius of 20 cm and
  an emittance of $2×10^−7$m·rad. 

The quote is to show that there exists a balistic effect of gravity that is too small to affect beams at LHC, which at best can work with micron accuracies. Possible 1000km experiments cannot be with charged tracks within our technology (maybe in space).
Any corrections for tides  are done by the "feel" of the operator of the beam, as the objective is to get the beams to collide, and for protons the electromagnetic effects will be stronger than any gravitational at the level of microns.
So any experimental verification of such claims, as twice the attraction of newtonian gravity, are not at present possible. There is an experiment which checks whether antihydrogen is attracted or repulsed, and sets limits, and that is as far as it goes with the present accelerators on interesting deviations of predictions.
