Classical and quantum scattering by a gravitational center
  The small angle scattering (by a gravitational field) of classical and quantum particles is considered and compared. It is suggested that the differences in small angle scattering of particles with spin 0, 1, 2 are due to the nonzero probability of forward scattering for particles described by a wave packet. It is suggested that measurements of the deflection of light in the vicinity of the Sun will decide which coordinate system is the privileged one. 
A.I.Nikishov