High-Q2 Delta (1232) electroproduction and QCD predictions.

Abstract

Analyses of the electroproduction of pions in the {Delta}(1232) region have been taken to suggest that the dominance of the magnetic dipole amplitude persists up to the highest momentum transfer available. Actually, magnetic dipole dominance is consistent with the data but is not required by it. We show that the high-momentum-transfer QCD prediction of equality, modulo notation, between the electric quadrupole and magnetic dipole amplitudes is also consistent with the high-momentum-transfer data. Thus, while the present data do restrict the multipole amplitudes, to distinguish the two main possibilities further measurements are needed, and we comment on these.