Study of N(1440) structure via γ*p→N(1440) transition

A Kaewsnod,A Limphirat,Y Yan,Z Zhao,K Xu,S Srisuphaphon,X Y Liu

doi:10.1103/physrevd.105.016008

A Kaewsnod, A Limphirat + Show 5 more

Open Access

https://doi.org/10.1103/physrevd.105.016008

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Abstract

We study the photoproduction of the $N(1440)$ resonance in $\gamma^*p\to N^*$ process in quark models, where the $N(1440)$ takes different wave functions: first radial excitation of the nucleon imported from low-lying baryon mass spectrum calculations, a general radial excitation of the nucleon, and a $q^3$ state with positive parity. The comparison between the theoretical results and experimental data on the helicity amplitudes $A_{1/2}$ and $S_{1/2}$ and the analysis of the spatial wave function of the $N(1440)$ resonance reveal that the $N(1440)$ resonance is mainly the $q^3$ first radial excitation.

Highlights

In recent years, the experiments on electro- and photoproductions of particles have accumulated a large amount of data of helicity amplitudes over the four-momentum transfer Q2 of virtual photons [1,2,3,4]
We study the γÃp → NÃ transition of the Nð1440Þ resonance in quark models to reveal the inner structure of the resonance
The comparison between the theoretical results and experimental data on the helicity amplitudes A1=2 and S1=2 and the analysis of the spatial wave function of the Nð1440Þ resonance reveal that the Nð1440Þ resonance is mainly the q3 first radial excitation

Summary

INTRODUCTION

The experiments on electro- and photoproductions of particles have accumulated a large amount of data of helicity amplitudes over the four-momentum transfer Q2 of virtual photons [1,2,3,4]. The nature of the Roper resonance is still an open question, which is implied by its large decay width [17] as well as the mass ordering with the lowest negative-parity baryon resonance states Nð1520Þ and Nð1535Þ [18]. Mass spectrum calculations [19,20], where the mass ordering problem of Nð1440Þ, Nð1520Þ, and Nð1535Þ is tackled by including ground state light pentaquark components in the negative-parity nucleon resonances, point out that the Nð1440Þ might be mainly the first radial excitation of the nucleon.

PROTON FORM FACTOR OF THREE-QUARK CORE

HELICITY AMPLITUDES WITH Nð1440Þ AS THREE QUARK STATES

EXTRACTION OF QUARK DISTRIBUTION OF Nð1440Þ

SUMMARY