$\gamma^\ast N \to N^\ast (1520)$ transition form factors in light cone QCD

TL;DR

This paper calculates the transition form factors for the $ o N^*(1520)$ reaction using light cone QCD sum rules, providing theoretical predictions for helicity amplitudes and comparing them with experimental data.

Contribution

It introduces a new application of light cone QCD sum rules to compute multipole form factors for the $ o N^*(1520)$ transition, linking them to helicity amplitudes.

Findings

Calculated $Q^2$ dependence of helicity amplitudes.

Compared results with spectator model predictions.

Aligned theoretical results with experimental data.

Abstract

The $\gamma^\ast N \to N^\ast (1520)$ reaction is studied in framework of the light cone QCD sum rules method. The sum rules for the multipole form factors, namely, for the magnetic dipole $G_M(Q^2)$, electric quadrupole $G_E(Q^2)$, and Coulomb quadrupole $G_C(Q^2)$, form factors responsible for for the $\gamma^\ast N \to N^\ast (1520)$ transition are derived. Using these sum rules, the helicity amplitudes are presented as the combinations of these multipole form factors, and their $Q^2$ dependences are studied. We compare our results on the helicity amplitudes with those of the spectator model predictions, and with the existing experimental data.