G. Salmè

Electromagnetic form factors of the ϱ meson in a light-front constituent quark model

Abstract The electromagnetic form factors of the ϱ meson are evaluated adopting a relativistic constituent quark model based on the light-front formalism, and using a meson wave function with the high-momentum tail generated by the one-gluon-exchange interaction. The breakdown of the rotational covariance for the one-body component of the current operator is investigated and the sensitivity of the ratio of the ϱ-meson form factors to the pion (charge) form factor to the spin-dependent component of the effective q q interaction is illustrated.

Pion generalized parton distributions with covariant and light-front constituent quark models

We investigate the model dependence of no-helicity flip generalized parton distribution of the pion upon different approaches for the quark-hadron and quark-photon vertices, in the spacelike region. In order to obtain information on contributions from both the valence and the nonvalence regions, we compare results for spacelike momentum transfers obtained from (i) an analytic covariant model with a bare quark-photon vertex, (ii) a light-front approach with a quark-photon vertex dressed through a microscopic vector-meson model, and (iii) a light-front approach based on the relativistic Hamiltonian dynamics. Our comparisons lead us to infer the same dynamical mechanism, the one-gluon-exchange dominance at short distances, as a source of both the electromagnetic form factor at large momentum transfer and the parton distribution close to the end points. The expected collinear behavior of the generalized parton distributions at high-momentum transfer, i.e. a maximum for x{approx}1, is also illustrated, independently of the different approaches. Finally, a comparison with recent lattice calculations of the gravitational form factors is presented.

Spacelike and timelike pion electromagnetic form factor and Fock state components within the light-front dynamics

The simultaneous investigation of the pion electromagnetic form factor in the space- and timelike regions within a light-front model allows one to address the issue of nonvalence components of the pion and photon wave functions. Our relativistic approach is based on a microscopic vector-meson-dominance model for the dressed vertex where a photon decays in a quark-antiquark pair, and on a simple parametrization for the emission or absorption of a pion by a quark. The results show an excellent agreement in the space like region up to -10 (GeV/c){sup 2}, while in timelike region the model produces reasonable results up to 10 (GeV/c){sup 2}.

Neutron structure function F(2)**n (x) from deep inelastic electron scattering off few nucleon systems

The possibility of a reliable extraction of the neutron deep inelastic structure function,

Charge form factor of {pi} and {ital K} mesons

F_2^n(x)

Nucleon Electromagnetic Form Factors in the Timelike Region

, for

Deuteron Magnetic and Quadrupole Moments with a Poincare Covariant Current Operator in the Front-Form Dynamics

x < 0.85

Electromagnetic and weak current operators for interacting systems within the front-form dynamics

from joint measurements of deep inelastic structure functions of deuteron,

Projecting the Bethe–Salpeter Equation onto the Light-Front and Back: A Short Review

^{3}He

A light-front description of electromagnetic form factors for J ≤ 32 hadrons

and