Nucleon resonances with spin $\frac{3}{2}$ and isospin $\frac{1}{2}$

TL;DR

This paper uses QCD sum rules to calculate the masses and residues of nucleon resonances with spin 3/2 and isospin 1/2, aiding understanding of their structure and missing states.

Contribution

It provides theoretical mass and residue calculations for specific nucleon resonances using QCD sum rules, consistent with experimental data.

Findings

Masses match PDG ranges for N*(1520), N*(1700), N*(1720)

Calculated residues can inform interaction studies

Supports the quark model and QCD understanding

Abstract

Investigation of the nucleon's excited states has always become an important research topic because of the rich information they provide. Since their first observation, dating back about 70 years, the investigation of their various parameters contributed both to the development of the quark model and better understanding of the QCD as the theory of strong interaction. Their investigation still has importance. The researches conducted on the nucleon excited states are helpful to probe missing resonances predicted by the quark model but not observed yet. With this motivation, we study the low lying nucleon resonance with $I(J^P)=\frac{1}{2}(\frac{3}{2}^{-})$ and its corresponding orbital and radial excitations with $I(J^P)=\frac{1}{2}(\frac{3}{2}^+)$ and $I(J^P)=\frac{1}{2}(\frac{3}{2}^-)$, respectively. Using the QCD sum rule method, we calculate the masses and pole residues of these states. The obtained mass results are consistent with the mass ranges presented in PDG for the resonances $N^*(1520)(3/2^-)$, $N^*(1700)(3/2^-)$, and $N^*(1720)(3/2^+)$. The results of masses and residues of these states may be used as input parameters to calculate various quantities related to their electromagnetic, weak and strong interactions with other particles with the aim of getting more information on their nature and structure.