Masses of positive- and negative-parity hadron ground-states, including those with heavy quarks

TL;DR

This paper uses a symmetry-preserving contact interaction model to compute and analyze the spectra of various mesons and baryons, including those with heavy quarks, achieving high accuracy and predicting new states.

Contribution

It introduces a novel algebraic approach to baryon and meson spectra that accurately reproduces known data and predicts new states, emphasizing the role of diquark correlations.

Findings

Reproduces 64 known baryon masses with ~1.4% accuracy.

Predicts many baryon states yet to be observed.

Highlights the importance of nonpointlike diquark correlations.

Abstract

A symmetry-preserving treatment of a vector$\times$vector contact interaction is used to compute spectra of ground-state $J^P = 0^\pm, 1^\pm$ $(f\bar g)$ mesons, their partner diquark correlations, and $J^P=1/2^\pm, 3/2^\pm$ $(fgh)$ baryons, where $f,g,h \in \{u,d,s,c,b\}$. Results for the leptonic decay constants of all mesons are also obtained, including scalar and pseudovector states involving heavy quarks. The spectrum of baryons produced by this chiefly algebraic approach reproduces the 64 masses known empirically or computed using lattice-regularised quantum chromodynamics with an accuracy of 1.4(1.2)%. It also has the richness of states typical of constituent-quark models and predicts many baryon states that have not yet been observed. The study indicates that dynamical, nonpointlike diquark correlations play an important role in all baryons; and, typically, the lightest allowed diquark is the most important component of a baryon's Faddeev amplitude.