Fitting the exotic hadron spectrum with an additional quark

TL;DR

This paper proposes that introducing a seventh quark flavor around 2.9 GeV can explain the spectrum of exotic hidden-charm hadrons, supported by a model including light scalar bosons.

Contribution

It introduces a new quark flavor hypothesis and a model incorporating light scalar bosons to explain exotic hadron spectra.

Findings

The proposed seventh quark has a mass of approximately 2.9 GeV and charge -1/3.

The model reproduces observed production and decay modes of exotic hadrons.

Including light scalar bosons aligns the model with experimental data.

Abstract

Most of the exotic hidden-charm hadrons discovered over the last 20 years fit neatly into the quark model as normal mesons and baryons if the existence of a seventh flavor of quark is hypothesized. For the quark to reproduce the spectrum (mass, spin, parity) of exotic hadrons, it would have to have a mass of $\sim$2.9 GeV and a charge of $-\tfrac{1}{3}$. The observed production and decay modes of these hadrons can be reproduced by a model that also includes light scalar bosons.