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We study consistently the pions static observables and the elastic and gamma*gamma -> pi^0 transition form factors within a light-front model. Consistency requires that all calculations are performed within a given model with the same and single adjusted length or mass-scale parameter of the associated pion bound-state wave function. Our results agree well with all extent data including recent Belle data on the gamma*gamma -> pi^0 form factor at large q^2, yet the BaBar data on this transition form factor resists a sensible comparison. We relax the initial constraint on the bound-state wave function and show the BaBar data can partially be accommodated. This, however, comes at the cost of a hard elastic form factor not in agreement with experiment. Moreover, the pion charge radius is about 40% smaller than its experimentally determined value. It is argued that a decreasing charge radius produces an ever harder form factor with a bound-state amplitude difficultly reconcilable with soft QCD. We also discuss why vector dominance type models for the photon-quark vertex, based on analyticity and crossing symmetry, are unlikely to reproduce the litigious transition form factor data.
Electromagnetic form factors of hyperons ($Lambda$, $Sigma$, $Xi$) in the timelike region, accessible in the reaction $e^+e^- to bar YY$, are studied. The focus is on energies close to the reaction thresholds, where the properties of these form facto
A symmetry-preserving approach to the two valence-body continuum bound-state problem is used to calculate the elastic electromagnetic form factors of the $rho$-meson and subsequently to study the evolution of vector-meson form factors with current-qu
A synopsis exemplifying the employment of Dyson-Schwinger equations in the calculation and explanation of hadron electromagnetic form factors and related phenomena. In particular the contribution: presents the pion form factor computed simultaneously
A dressed-quark core contribution to nucleon electromagnetic form factors is calculated. It is defined by the solution of a Poincare covariant Faddeev equation in which dressed-quarks provide the elementary degree of freedom and correlations between
We summarise applications of Dyson-Schwinger equations to the theory and phenomenology of hadrons. Some exact results for pseudoscalar mesons are highlighted with details relating to the U_A(1) problem. We describe inferences from the gap equation re