On the Q2-dependence of the N → Nγ and Δ → Nγ transition form factors in a quark model at Q2 < 4 GeV2

Abstract

The specific features of the Q2-behaviour of the nucleon electromagnetic and axial-vector form factors and of the magnetic form factor of the Δ → Nγ transition at Q2 < 4 GeV2 which are, generally speaking, characteristic of perturbative QCD, are described within a relativistic quark model constructed in the infinite momentum frame. The prediction for the Q2-dependence of the ratio E1+/M1+ is obtained which is also similar to the perturbative QCD prediction.