Helicity amplitudes of $N(1520)$ and $N(1535)$ including pentaquark components

TL;DR

This paper studies the electromagnetic transition helicity amplitudes of the $N(1520)$ and $N(1535)$ resonances, showing that including pentaquark components in the model improves agreement with experimental data.

Contribution

It introduces a model incorporating both three-quark and pentaquark components to better explain helicity amplitudes of specific nucleon resonances.

Findings

Including pentaquark components improves data agreement.

Resonances may have significant pentaquark content.

Model aligns better with experimental measurements.

Abstract

We investigate the helicity amplitudes of the $N(1520)$ and $N(1535)$ resonances in the electromagnetic transition process $\gamma^*p\to N^*$, where the $N(1520)$ and $N(1535)$ are assumed to include both the $L=1$ three-quark and $L=0$ spatial symmetric $q^4\bar q$ pentaquark components. The helicity transition amplitudes $A_{1/2}$, $A_{3/2}$ (for spin 3/2 states) and $S_{1/2}$ are computed within the constituent quark model. The inclusion of the $q^4 \bar q$ pentaquark components via the $\gamma^*\to q\bar q$ diagram significantly improves the theoretical description of the helicity amplitudes for both $N(1520)$ and $N(1535)$, yielding a closer agreement with experimental data compared to the pure three-quark picture. The work reveals that the $N(1520)$ and $N(1535)$ resonances may contain a considerable pentaquark components.