Speaker
Description
Gravity independence on rotations or spin direction is
postulated in general relativity and experimentally
constrained for low energy, non-relativistic matter.
An evidence for high energy CP violation in gravitational
field has recently been found in the HERA Compton polarimeter's
2 spectra measured with electron and positron beams.
Here I report analysis results of 838 thousand spectra,
acquired during the 2004-2007 running period and tagged
by laser polarization state.
The tagged spectra allow to separate charge (C) and space (P)
parity contributions. While the C asymmetry is
contaminated by change of the accelerator parameters
for the electron and positron runs, the laser helicity frequent
flips eliminate most of the potential systematic errors.
Measured Compton edge energy asymmetry induced by the laser
helicity change is as high as (4.62 ± 0.06)x10^{-5}
which corresponds to helicity dependent gravitational potentials'
difference of (8.1 ± 0.1)x10^{-15}.
The measured sign applies a stronger gravitational coupling to
left helicity particles.
In case of the observed coupling universality i.e. energy
independence, the gravity will induce 3.69 ± 0.05 GHz and
2.01 ± 0.02$ MHz spin resonances in nuclei and atoms respectively.
