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SUMMARY:Fermion-antifermion phenomenology in Minkowski space
DTSTART;VALUE=DATE-TIME:20180515T192000Z
DTEND;VALUE=DATE-TIME:20180515T194000Z
DTSTAMP;VALUE=DATE-TIME:20211209T002447Z
UID:indico-contribution-3139@indico.jlab.org
DESCRIPTION:Speakers: Jorge Henrique De Alvarenga Nogueira (Instituto Tecn
ológico de Aeronáutica & 'La Sapienza' Università di Roma & INFN\, Sezi
one di Roma)\nThe advent of approaches based on the Euclidean space for st
udying\n hadron observables\, such as lattice QCD and Schwinger-Dyson equa
tions\, \n has been remarkable and responsible to produce important unders
tanding\n on the non-perturbative dynamical regime. \n\nHowever\, the qua
ntum field theory formulation in Minkowski space has subtle and\nessential
signatures as\, e.g.\, the ones related to the spin degrees of\n freedom
\, that require to be evaluated in a theoretical framework developed \n in
the physical space\, where the dynamical processes take place. One import
ant tool \n is the Fock space expansion\, which allows one to construct a
probabilistic \n description of hadrons and to explore relativistic effe
cts on the dynamics \n as\, e.g.\, through the analysis of the electromagn
etic (EM) form factors beyond the impulse approximation [1].\n\nIn recent
years\, studies based on actual solutions of the homogeneous\nBethe-Salpet
er equation directly in Minkowski space have becoming available. \nThis a
chievement makes\nfeasible to start phenomenological investigations of th
e hadron structure\, shedding light on the intrinsic dynamics that is form
ally and conceptually connected with the physical space\, i.e. the Minkows
ki one [2\,3]. \n The new framework for solving the Bethe-Salpeter equatio
n has a main \n ingredient given by the the so-called Nakanishi Integral R
epresentation of\n the Bethe-Salpeter amplitude that allows one to expli
citly deal with its\n analytic structure\, without resorting to the Wick
rotation. \n\nIn order to illustrate the phenomenological potential of the
aforementioned \nframework we explore the $0^-$ quark-antiquark bound sta
te\, by the solution of the coupled integral equations. The study is done
in the ladder\napproximation\, based on the suppression of the cross-ladde
r contribution found for bosonic systems [2].\n By taking the constituents
and exchanged-boson masses from\, \n e.g.\, lattice calculations\, dynami
cal observables \n like the light-cone momentum distributions are predicte
d. \n The decay constant $f_\\pi$ is also computed\, as well as the elec
tromagnetic form factors. Such a preliminary investigation of the phenomen
ology of what we call mock pion will allow\n to settle the framework where
one can develop more and more realistic description in Minkowski space.\n
\n[1] V. Gigante\, J. H. Alvarenga Nogueira\, E. Ydrefors\, C. Gutierrez\,
V. A. Karmanov and T. Frederico\, Phys. Rev. D 95\, 056012 (2017)\n\n[2]
J. H. Alvarenga Nogueira\, Chueng-Ryong Ji\, E. Ydrefors and T. Frederico\
, Phys. Lett. B 777\, 207-211 (2018)]\n\n[3] W. de Paula\, T. Frederico\,
G. Salmè\, M. Viviani\, R. Pimentel\, \n%Fermionic bound states in Minkow
ski space: light-cone singularities and structure\, \nEur. Phys. J. C 77\,
764 (2017)\n\nhttps://indico.jlab.org/event/252/contributions/3139/
LOCATION:Jefferson Lab - CEBAF Center F113
URL:https://indico.jlab.org/event/252/contributions/3139/
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