arXiv subjects

Giovanni Salme`

Publications and source records attributed to Giovanni Salme`.

6 recordsLinked to original sources

arXiv2022

The European Muon Collaboration effect in Light-Front Hamiltonian Dynamics

A rigorous light-front formalism for electron deep inelastic scattering on unpolarized nuclei, in Bjorken limit, is reported. It preserves Poincaré covariance, macroscopic locality, both number of particles and momentum sum rules. The scheme is applied to the A=3 iso-doublet, very relevant in view of the planned operation with unpolarized and polarized beams at the Electron-Ion Collider. At variance with previous light-front estimates, our procedure, including a realistic nuclear description and free-nucleon structure functions, predicts a sizeable European Muon Collaboration effect for $^3$He. This will allow to analyze deviations from the proposed baseline in terms of genuine QCD effects. The extension to heavier nuclei is straightforward, although numerically challenging.

nucl-th↗

arXiv2014

Solutions of the Bethe-Salpeter Equation in Minkowski space: a comparative study

The Bethe-Salpeter Equation for a two-scalar, S-wave bound system, interacting through a massive scalar, is investigated within the ladder approximation. By assuming a Nakanishi integral representation of the Bethe-Salpeter amplitude, one can deduce new integral equations that can be solved and quantitatively studied, overcoming the analytic difficulties of the Minkowski space. Finally, it is shown that the Light-front distributions of the valence state, directly obtained from the Bethe-Salpeter amplitude, open an effective window for studying the two-body dynamics.

hep-ph↗

arXiv2012

Nucleon Electromagnetic Form Factors in the Timelike Region

The electromagnetic form factors of the proton and the neutron in the timelike region are reviewed. In view of the forthcoming experimental projects devoted to investigate these observables, we present the current status of the field and we emphasize the relevant role, that accurate measurements, refined phenomenological analyses, as well as microscopic models will play with the goal of achieving deeper insights into the structure of the nucleon and its inner dynamics.

hep-ex↗

arXiv2010

Elastic electron-deuteron scattering and two-body current operators in the Light-Front Hamiltonian Dynamics

The electromagnetic properties of the deuteron are investigated within a Light-Front Hamiltonian Dynamics framework, with a current operator that contains both one-body and two-body contributions. In this work, we are considering new two-body contributions, with a dynamical nature generated within a Yukawa model and a structure inspired by a recent analysis of the current operator, that acts on the three-dimensional valence component and fulfills the Ward-Takahashi identity. Preliminary results for the magnetic moment are shown.

nucl-th↗

arXiv2010

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

The technique of projecting the four-dimensional two-body Bethe-Salpeter equation onto the three-dimensional Light-Front hypersurface, combined with the quasi-potential approach, is briefly illustrated, by placing a particular emphasis on the relation between the projection method and the effective dynamics of the valence component of the Light-Front wave function. Some details on how to construct the Fock expansion of both i) the Light-Front effective interaction and ii) the electromagnetic current operator, satisfying the proper Ward-Takahashi identity, will be presented, addressing the relevance of the Fock content in the operators living onto the Light-Front hypersurface. Finally, the generalization of the formalism to the three-particle case will be outlined.

nucl-th↗

arXiv2008

Electromagnetic Decays of Vector Mesons in a Covariant Model

A fully covariant model for describing the electromagnetic decay of Vector Mesons, both in light and in heavy sectors, is presented. The main ingredients of our approach are i) an Ansatz for the Bethe-Salpeter vertex for Vector Mesons, and ii) a Mandelstam-like formula for the electromagnetic decay constant. The free parameters of our approach are fixed through a comparison with the transverse momentum distribution obtained within a Light-Front Hamiltonian Dynamics framework with constituent quarks. Preliminary results for both the decays constants and the probability of the valence component are shown.

hep-ph↗