Related papers: Pion charge form factor and constraints from space…
The electromagnetic elastic form factors of pseudoscalar and vector mesons are analyzed for space-like momentum transfers in terms of relativistic quark models based on the Hamiltonian light-front formalism elaborated in different reference…
We discuss strong decays of baryon resonances within the concept of relativistic constituent quark models. In particular, we follow a Poincare-invariant approach along the point form of relativistic quantum mechanics. Here, we focus on…
We present the first systematic investigation of the Lorentz covariance of the charge form factor for a strongly coupled scalar theory in (3+1)-dimensions. Our results are based on the first non-perturbative solution of the scalar Yukawa…
We apply the point form of relativistic quantum mechanics to develop a Poincare invariant coupled-channel formalism for two-particle systems interacting via one-particle exchange. This approach takes the exchange particle explicitly into…
A global fit to the data from different collaborations (CELLO, CLEO, BaBar) on the pion-photon transition form factor is carried out using light-cone sum rules. The analysis includes the next-to-leading QCD radiative corrections and the…
We review in simple terms the covariant approaches to the canonical formulation of classical relativistic field theories (in particular gauge field theories and general relativity) and we discuss the relationships between these approaches…
We have reexamined the elastic pion form factor over a broad range of momentum transfers with the mass evolution from current quark to constituent quark being taken into account. We have also studied the effect of Sudakov form factors, of…
We propose an effective lagrangian for the coupling of the neutral pion with gluons whose strength is determined by a low energy theorem. We calculate the contribution of the gluonic components arising from this interaction to the pion…
The axial form factor G_A of the nucleon is investigated for the Goldstone-boson-exchange constituent quark model using the point-form approach to relativistic quantum mechanics. The results, being covariant, show large contributions from…
Motivated by the planned measurements of the time-like electromagnetic proton form factors an exploratory study of the time-like electromagnetic pion form factor is presented in a formalism which describes mesons as Poincar\'e-invariant…
The light-front approach is applied to calculate the electromagnetic current for quark-antiquark bound states for the pion. The pion electromagnetic form factor is obtnaide from the "+" and "-" components of the electromagnetic current in…
The pion electromagnetic form factor is calculated with a light-front quark model. The "plus" and "minus" component of the electromagnetic current are used to calculate the electromagnetic form factor in the Breit frame with two models for…
This paper introduces "time-dependent basis light-front quantization", which is a covariant, nonperturbative, and first principles numerical approach to time-dependent problems in quantum field theory. We demonstrate this approach by…
Relativistic spin states are convention dependent. In this work we prove that the zero momentum-transfer limits of the leading two form factors in the decomposition of the energy-momentum tensor matrix elements are independent of this…
We carefully investigate the reliability of the propagator Pole Approximation, i.e, the approximation of retaining only the propagator in the evaluation of the Mandelstam covariant expression for the eletromagnetic current of the pion.…
We analyze the matrix element of the electroweak current between $q \qb$ vector meson states in the framework of a covariant extension of the light-front formalism. The light-front matrix element of a one-body current is naturally…
We present a brief survey of some results on electroweak properties of composite systems that are obtained in the frameworks of our version of the instant form of relativistic quantum mechanics (RQM). Our approach describes well the $\pi$-…
We study the form factors of vector mesons using a covariant fermion field theory model in $(3+1)$ dimensions. Performing a light-front calculation in the $q^+ =0$ frame in parallel with a manifestly covariant calculation, we note the…
We introduce a covariant approach in Minkowski space for the description of quarks and mesons that exhibits both chiral-symmetry breaking and confinement. In a simple model for the interquark interaction the quark mass function is obtained…
This talk presents an introduction to the use of dispersion relations to constrain the shapes of hadronic form factors consistent with QCD. The applications described include methods for studying |V_{cb}| and |V_{ub}|, the strange quark…