Electromagnetic form factors of the Delta(1232) in Dual-Large N_c QCD

Abstract

The three electromagnetic form factors of the $\Delta (1232)$ resonance, $G_M^{\ast }(q^2)$, $G_E^{\ast }(q^2)$, and $G_C^{\ast }(q^2)$ are obtained in the space-like region using a Dual Resonance Model realization of QCD in the large $N_c$ limit (Dual-${QCD}_{\infty }$). Each form factor involves a single free parameter which is fixed by fitting data on $G_M^{\ast }(q^2)$, and on the ratios $R_{EM}(q^2)$ and $R_{SM}(q^2)$. Good agreement with experiment is obtained for all three quantities. Results are then used to predict the $q^2$-dependence of the chiral effective-field theory form factors $g_M(q^2)$, $g_E(q^2)$, and $g_C(q^2)$.