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Investigation of the Δð1232Þ resonance substructure in the pγ* → Δð1232Þ process through helicity amplitudes
Author(s)
Date Issued
February 10, 2026
Type
Article
Abstract
The substructure of the Δð1232Þ resonance is studied in the pγ* → Δð1232Þ transition via helicity amplitudes within a quark-model framework that treats baryons as three-quark systems and includes both quark-core and meson-cloud contributions. In the calculation of the transition amplitudes, the proton wave function is Lorentz boosted from the proton rest frame to the Δð1232Þ resonance rest frame. The comparison of the calculated amplitudes A1=2, A3=2, and S1=2 with experimental data indicates a nonnegligible L ¼ 2 admixture in the Δð1232Þ, about 80% of the Δð1232Þ wave function in the S wave and 20% in the D wave. In particular, the S1=2 amplitude is found to be dominated by the L ¼ 2 quark-core component rather than the L ¼ 0 part. The results challenge the traditional understanding that the Δð1232Þ baryon is dominantly an L ¼ 0 state.
Citation
Physical Review D, 113(3), 2026