γ(∗) + 𝐍(𝟗𝟒𝟎)⁢𝟏/𝟐+ → 𝐍(𝟏𝟓𝟐𝟎)𝟑/𝟐− helicity amplitudes and transition form factors

Abstract

We recently reported new results on the 𝛾(*)+𝑁⁡(940)⁢1/2+→Δ⁡(1700)⁢ 3/2− transition form factors using a symmetry-preserving treatment of a vector ⊗vector contact interaction (SCI) within a coupled formalism based on the Dyson-Schwinger, Bethe-Salpeter, and Faddeev equations. In this work, we extend our investigation to the 𝛾(*)+𝑁⁡(940)⁢1/2+ →𝑁⁡(1520)⁢3/2− transition. Our computed transition form factors show reasonable agreement with experimental data at large photon virtualities. However, deviations emerge at low 𝑄2, where experimental results exhibit a sharper variation than theoretical predictions. This discrepancy is expected, as these continuum QCD analyses account only for the quark-core of baryons, while low photon virtualities are dominated by meson cloud effects. We anticipate that these analytical predictions, based on the simplified SCI framework, will serve as a valuable benchmark for more refined studies and QCD-based truncations that incorporate quark angular momentum and the contributions of scalar and vector diquarks.