Related papers: Vector Meson Dominance and Free Quarks
In semi-leptonic and other weak decays of mesons, the hadronic matrix elements of the operators in the weak Hamiltonian are parametrized by standard sets of independent, Lorentz invariant, form factors. For the case of pseudoscalar to…
The implications of the pion (meson) degrees of freedom for baryon properties, taken at the constituent quark and baryon levels are compared. It is shown that there is a dramatic qualitative difference between two approaches.
We study the electromagnetic form factors, decay constants and charge radii of the pion and kaon within the framework of light-front field theory formalism where we use an ansatz for the quark-meson interaction bound-state function which is…
We discuss a constraint of conformal symmetry in the analysis of the pion form factor. The usual power-law behavior of the form factor obtained in the perturbative QCD analysis can also be attained by taking negligible quark masses in the…
The hypothesis is scrutinized that the weak interaction of hadronic systems at low energies is dominated by the coupling of the pseudoscalar, vector, and axial-vector mesons to the weak gauge bosons. The strength of the weak coupling of the…
An exploratory study of the time-like pion electromagnetic form factor in a Poincar\'e-covariant bound state formalism in the isospin symmetric limit is presented. Starting from a quark interaction kernel representing gluon-intermediated…
I introduce the properties of the light axial-vector mesons. The branching ratios, longitudinal fractions and direct CP asymmetries of the related charmless two-body B decays into final states involving two axial-vector mesons ($AA$) or one…
We study the nucleon electromagnetic (EM) form factors in symmetric nuclear matter as well as in vacuum within a light-front approach using the in-medium inputs calculated by the quark-meson coupling model. The same in-medium quark…
The kaon electromagnetic (e.m.) form factor is reviewed considering a light-front constituent quark model. In this approach, it is discussed the relevance of the quark-antiquark pair terms for the full covariance of the e.m. current. It is…
The pion electromagnetic form factor is calculated at lower and higher momentum transfer in order to explore constituent quark models and the differences among those models. In particular, the light-front constituent quark model is utilized…
Motivated by recent measurements at J-Lab, the pion electromagnetic form-factor is investigated with quenched domain wall fermions and a renormalization group improved gauge action called DBW2. We see that quark mass dependence of the…
A model is developed for electromagnetic form factors of the charged and neutral K-mesons. The formalism is based on ChPT Lagrangians with vector mesons. The form factors, calculated without fitting parameters, are in a good agreement with…
We summarize our recent results for the quark loop part of the light-by-light scattering contribution as well as the hadronic vacuum polarisation contributions to the anomalous magnetic moment of the muon. In particular we focus on the role…
This talk presents issues pertaining to the quark structure of the pion within QCD, both from the theoretical and from the experimental point of view. We review and discuss the pion-photon transition form factor and the pion's…
Recent results by Benayoun et al. comparing the predictions of a range of existing models based on the Vector Meson Dominance hypothesis are summarized and discussed. These are compared with data on e+ e- -> pi+ pi- and e+ e- -> mu+ mu-…
We discuss the vector meson masses within the context of Chiral Perturbation Theory performing an expansion in terms of the momenta, quark masses and 1/Nc. We extend the previous analysis to include isospin breaking effects and also include…
We report the first lattice QCD computation of pion and kaon electromagnetic form factors, $F_M(Q^2)$, at large momentum transfer up to 10 and 28 $\mathrm{GeV}^2$, respectively. Utilizing physical masses and two fine lattices, we achieve…
We present an investigation of the electromagnetic pion form factor, $F_\pi(Q^2)$, at small values of the four-momentum transfer $Q^2$ ($\lesssim 0.25$ GeV$^2$), based on the gauge configurations generated by European Twisted Mass…
The main assumption of the model is that in soft processes mesons behave like systems made of valence quarks and an effective vacuum- like field. The 4-momentum of the latter represents the relativistic generalization of the potential…
In most meson strong decay and unquenched (coupled-channel) quark models, the pair-creation operator is a scalar product of vectors in the spin and spatial degrees of freedom. While differing in the spatial part, most models have the same…