Nucleon resonances with spin and isospin

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 a better understanding of the QCD as the theory of strong interaction. Their investigation still has importance. The research conducted on the nucleon excited states is helpful to probe the missing resonances predicted by the quark model but not observed yet. With this motivation, we study the low lying nucleon resonance with and its corresponding orbital and radial excitations with and , 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 natures and structures.