Speaker
Mr
Jorge Henrique De Alvarenga Nogueira
(Instituto Tecnológico de Aeronáutica & 'La Sapienza' Università di Roma & INFN, Sezione di Roma)
Description
The advent of approaches based on the Euclidean space for studying
hadron observables, such as lattice QCD and Schwinger-Dyson equations,
has been remarkable and responsible to produce important understanding
on the non-perturbative dynamical regime.
However, the quantum field theory formulation in Minkowski space has subtle and
essential signatures as, e.g., the ones related to the spin degrees of
freedom, that require to be evaluated in a theoretical framework developed
in the physical space, where the dynamical processes take place. One important tool
is the Fock space expansion, which allows one to construct a probabilistic
description of hadrons and to explore relativistic effects on the dynamics
as, e.g., through the analysis of the electromagnetic (EM) form factors beyond the impulse approximation [1].
In recent years, studies based on actual solutions of the homogeneous
Bethe-Salpeter equation directly in Minkowski space have becoming available.
This achievement makes
feasible to start phenomenological investigations of the hadron structure, shedding light on the intrinsic dynamics that is formally and conceptually connected with the physical space, i.e. the Minkowski one [2,3].
The new framework for solving the Bethe-Salpeter equation has a main
ingredient given by the the so-called Nakanishi Integral Representation of
the Bethe-Salpeter amplitude that allows one to explicitly deal with its
analytic structure, without resorting to the Wick rotation.
In order to illustrate the phenomenological potential of the aforementioned
framework we explore the $0^-$ quark-antiquark bound state, by the solution of the coupled integral equations. The study is done in the ladder
approximation, based on the suppression of the cross-ladder contribution found for bosonic systems [2].
By taking the constituents and exchanged-boson masses from,
e.g., lattice calculations, dynamical observables
like the light-cone momentum distributions are predicted.
The decay constant $f_\pi$ is also computed, as well as the electromagnetic form factors. Such a preliminary investigation of the phenomenology of what we call mock pion will allow
to settle the framework where one can develop more and more realistic description in Minkowski space.
[1] V. Gigante, J. H. Alvarenga Nogueira, E. Ydrefors, C. Gutierrez, V. A. Karmanov and T. Frederico, Phys. Rev. D 95, 056012 (2017)
[2] J. H. Alvarenga Nogueira, Chueng-Ryong Ji, E. Ydrefors and T. Frederico, Phys. Lett. B 777, 207-211 (2018)]
[3] W. de Paula, T. Frederico, G. Salmè, M. Viviani, R. Pimentel,
%Fermionic bound states in Minkowski space: light-cone singularities and structure,
Eur. Phys. J. C 77, 764 (2017)
Primary author
Mr
Jorge Henrique De Alvarenga Nogueira
(Instituto Tecnológico de Aeronáutica & 'La Sapienza' Università di Roma & INFN, Sezione di Roma)
Co-authors
Dr
Cédric Mezrag
(Argonne National Laboratory)
Dr
Emanuel Ydrefors
(Instituto de Aeronautica)
Dr
Giovanni Salmè
(INFN, Sezione di Roma)
Prof.
Tobias Frederico
(Instituto Tecnologico de Aeronautica)
Prof.
Wayne De Paula
(ITA)
