The ΔNγ electromagnetic transition form factors GM∗(q2) and GE∗(q2) Original Research Article

A parameter-free, nonperturbative calculation of the ΔNγ electromagnetic transition amplitudes View the MathML source, View the MathML source, and the resonant multipole ratio REM(q2)≡E1+3/2(q2)/M1+3/2(q2) is performed in terms of the well-known nucleon isovector Sachs form factor GMV. Our methods are fully relativistic with conservation of the electromagnetic current guaranteed. We find that View the MathML source decreases more rapidly than the nucleon dipole form factor when −q2≳1 GeV2/c2 and that REM(q2) remains small even for very high four-momentum transfer implying that the perturbative QCD prediction REM(q2)→1 is purely asymptotic and is valid only for extremely high |q2|.