Q2independence ofQF2/F1,Poincaré invariance, and the nonconservation of helicity

Abstract
A relativistic constituent quark model is found to reproduce the recent data regarding the ratio of proton form factors, F2(Q2)/F1(Q2). We show that imposing Poincaré invariance leads to substantial violation of the helicity conservation rule, and an analytic result that the ratio F2(Q2)/F1(Q2)1/Q for intermediate values of Q2.