A covariant model for the gamma N -> N(1535) transition at high momentum transfer

TL;DR

This paper develops a covariant relativistic quark model to analyze the gamma N -> N(1535) transition, focusing on high momentum transfer regions and comparing theoretical predictions with experimental data.

Contribution

It extends the covariant spectator quark model to the N(1535) resonance, enabling calculation of valence quark contributions to transition form factors at high Q^2.

Findings

Model accurately predicts form factors F1* and F2* at high Q^2.

Results agree with experimental helicity amplitudes A_1/2 and S_1/2.

Model validity limited to Q^2 > 2.3 GeV^2.

Abstract

A relativistic constituent quark model is applied to the gamma N -> N(1535) transition. The N(1535) wave function is determined by extending the covariant spectator quark model, previously developed for the nucleon, to the S11 resonance. The model allows us to calculate the valence quark contributions to the gamma N -> N(1535) transition form factors. Because of the nucleon and N(1535) structure the model is valid only for Q^2> 2.3 GeV^2. The results are compared with the experimental data for the electromagnetic form factors F1* and F2* and the helicity amplitudes A_1/2 and S_1/2, at high Q^2.