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

Abstract

A symmetry-preserving treatment of a vector $$\times $$ × vector contact interaction is used to compute spectra of ground-state $$J^P = 0^\pm , 1^\pm $$ J P = 0 ± , 1 ± $$(f{\bar{g}})$$ ( f g ¯ ) mesons, their partner diquark correlations, and $$J^P=1/2^\pm , 3/2^\pm $$ J P = 1 / 2 ± , 3 / 2 ± (fgh) baryons, where $$f,g,h \in \{u,d,s,c,b\}$$ f , g , h ∈ { 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.

Mesons and Baryons: Parity Partners

“…In this choice, the coupling constant and the ultraviolet regulator vary as a function of the quark mass. This behavior was first suggested in [31] and later adopted in several subsequent works [9,[32][33][34][35].…”

Concerning pion parton distributions

“…Since it provides a largely algebraic framework, the SCI has been widely used [68,[84][85][86][87] to set benchmarks for more complex studies using QCD-kindred interactions.…”

Quark anomalous magnetic moment and its effects on the ρ meson properties

“…Besides preserving the relevant symmetries, the CI model typically yields semialgebraic expressions and captures the nonperturbative traits of QCD [28,38,39]. In addition, the CI model produces sensible results for the hadron mass spectrum [40][41][42][43], including tetraquarks [44], while also providing crucial benchmarks for many hadron structural properties [28][29][30][45][46][47][48]. The following sections are dedicated to illustrate some of the implications of the gluon model Ansatz from Eq.…”

“…In neither case, RL nor MRL, the ACM term has been incorporated; as a consequence, m a 1 is visibly underestimated. Often in CI model literature [40,43,53], SO repulsion is mimicked by attaching a multiplicative factor g so to the RL kernel in the corresponding channels, tuned as g so ¼ 0.24 to produce the empirical a 1 − ρ mass splitting. With the ρ meson mass computed in the CI-MRL truncation, g so ≈ 1=2 yields the value m a 1 − m ρ ≈ 0.45 GeV.…”