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Chiral limit of a fermion-scalar (1/2) + system in covariant gauges

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Autor(es):
Noronha, A. ; de Paula, W. ; Nogueira, J. H. de Alvarenga ; Frederico, T. ; Pace, E. ; Salme, G.
Número total de Autores: 6
Tipo de documento: Artigo Científico
Fonte: PHYSICAL REVIEW D; v. 107, n. 9, p. 10-pg., 2023-05-23.
Resumo

The homogeneous Bethe-Salpeter equation (BSE) of a (1/2)+ bound system, that has both fermionic and bosonic degrees of freedom, that we call a mock nucleon, is studied in Minkowski space, in order to analyze the chiral limit in covariant gauges. After adopting an interaction kernel built with a one-particle exchange, the chi-BSE is numerically solved by means of the Nakanishi integral representation and light -front projection. Noteworthy, the chiral limit induces a scale invariance of the model and consequently generates a wealth of striking features: (i) it reduces the number of nontrivial Nakanishi weight functions to only one; (ii) the form of the surviving weight function has a factorized dependence on the two relevant variables, compact and noncompact; and (iii) the coupling constant becomes an explicit function of the real exponent governing the power-law falloff of the nontrivial Nakanishi weight function. The thorough investigation at large transverse momentum of light-front Bethe-Salpeter amplitudes, obtained with massive constituents, provides a confirmation of the expected universal power-law falloff, with exponents predicted by our nonperturbative framework. Finally, one can shed light on the exponents that govern the approach to the upper extremum of the longitudinal-momentum fraction distribution function of the mock nucleon, when the coupling constant varies. (AU)

Processo FAPESP: 19/07767-1 - Reações nucleares com núcleos fracamente ligados ou com estrutura de cluster, radioativos e estáveis
Beneficiário:Leandro Romero Gasques
Modalidade de apoio: Auxílio à Pesquisa - Temático
Processo FAPESP: 17/05660-0 - Estudos teóricos da estrutura e reações de núcleos exóticos e sistemas de muitos corpos
Beneficiário:Brett Vern Carlson
Modalidade de apoio: Auxílio à Pesquisa - Temático