The baryon spectrum and the hypercentral Constituent Quark Model

TL;DR

This paper uses the hypercentral Constituent Quark Model to analyze the baryon spectrum, showing it better accounts for observed negative parity states and reduces the missing resonance problem compared to the harmonic oscillator model.

Contribution

The study demonstrates that the hypercentral Constituent Quark Model effectively explains recent baryon states, especially negative parity states, with fewer missing resonances than traditional models.

Findings

Negative parity states fit within lower shells of hCQM

Reduces the missing resonance problem in baryon spectrum

Better agreement with recent experimental observations

Abstract

The description of the baryon spectrum is performed using the hypercentral Consituent Quark Model (hCQM), mainly in comparison with the harmonic oscillator (h.o.). Recentlly many new states, at various levels of confidence have been observed, leading to a softening of the missing resonance problem in the case of positive parity states. However, the number of negative states is higher that predicted by the commonly used h.o. scheme and therefore one is forced to take into account also the higher energy shells, which contain an overall number of states much greater than the observed one. It is shown that, thanks to the peculiar level scheme of the hCQM, the recently observed negative parity states can be considered as belonging to the lower shells, keeping the missing resonance problem within more acceptable limits.