Electromagnetic structure and weak decay of pseudoscalar mesons in a light-front QCD-inspired model

Abstract

We study the scaling of the 3 S 1 − 1 S 0 meson mass splitting and the pseudoscalar weak decay constants with the mass of the meson, as seen in the available experimental data. We use an effective light-front QCD-inspired dynamical model regulated at short-distances to describe the valence component of the pseudoscalar mesons. The experimentally known values of the mass splittings, decay constants (from global lattice-QCD averages) and the pion charge form factor up to 4 [GeV/c] 2 are reasonably described by the model.

A covariant investigation of Neutral Vector Mesons: dynamical properties and electromagnetic decay widths

“…It should be pointed out that while the model of Ref. [4] yields reasonable results for the light sector (let us remind that the confining interaction for the squared mass operator of [4] is parabolic), in the heavy sector the model of Ref. [5] seems to behave better (for this model a linear confining interaction is considered in the mass operator).…”

“…In order to implement our procedure for fixing the free parameters in Λ V M , we have first evaluated n HD V M (k ⊥ ) by adopting the eigenfunctions obtained by using the model mass operators of both Refs. [4] and [5], and then we have minimized the difference |n val (k ⊥ )− n HD V M (k ⊥ )|. It should be pointed out that the VM spectra are satisfactorily reproduced for each VM investigated in this contribution.…”

“…The free parameters present in the Ansatz for each VM are fixed by comparing the so-called valence transverse-momentum distribution, n(k ⊥ ), with the same quantity evaluated within a Light-Front Hamiltonian Dynamics (LFHD) approach exploiting the eigenfunctions of two phenomenological mass operators, presented in Refs. [4] and [5], and able to reproduce the VM spectra. It should be pointed out that the free parameters represent an effective way for including some non perturbative features in our analytical Ansatz.…”

“…The mass operator corresponds to the one in Ref. [4] (see [10] for details). The quark masses adopted for the actual evaluation are also listed.…”

“…As an example of the reliability of the adopted LFHD models, the masses of the considered neutral VMs for the ground states are compared with the corresponding experimental values in Tables 1 and 2 for the mass operators of Refs. [4] and [5], respectively. Indeed, also the masses of the first three/four (depending upon the considered VM) excited states are well reproduced by the model mass operators.…”