QCD string in excited heavy-light mesons and heavy-quark hybrids

TL;DR

This paper uses a simplified QCD string model with only seven parameters to predict the masses of excited heavy-light mesons and hybrids, comparing results with experimental data and suggesting new quantum numbers.

Contribution

It introduces a reduced-parameter QCD string model to accurately predict heavy-light meson and hybrid spectra, extending understanding of their mass spectra.

Findings

Model parameters are fixed using well-established states.

Predicted masses align with experimental data.

Suggestions for unmeasured quantum numbers in charmonium and bottomonium.

Abstract

The QCD string model is employed to evaluate the masses of orbitally and radially excited heavy-light mesons and lightest hybrids in the spectrum of charmonium and bottomonium. The number of parameters of the model is reduced to only seven which are the string tension, the two values of the strong coupling constant (one for heavy-light and $\bar{c}c$ mesons and one for $\bar{b}b$ mesons), and the four overall spectrum shift constants which depend on the quark contents of the particular meson or hybrid family. A few well-established states in the spectrum of heavy-light and heavy-heavy mesons are used to fix these parameters, and then the masses of other mesons and hybrids come out as predictions of the model which are confronted with the existing experimental data, and a few suggestions are made concerning yet not measured quantum numbers of some states in the spectrum of charmonium and bottomonium.