Frame Dependence of Spin-One Angular Conditions in Light Front Dynamics
Abstract
We elaborate the frame dependence of the angular conditions for spin-1 form factors. An extra angular condition is found in addition to the usual angular condition relating the four helicity amplitudes. Investigating the frame-dependence of the angular conditions, we find that the extra angular condition is in general as complicated as the usual one, although it becomes very simple in the q^+ = 0 frame involving only two helicity amplitudes. It is confirmed that the angular conditions are identical in frames that are connected by kinematical transformations. The high Q^2 behaviors of the physical form factors and the limiting behaviors in special reference frames are also discussed.