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Pion off-shell electromagnetic form factors: Data extraction and model analysis

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Autor(es):
Choi, Ho-Meoyng ; Frederico, T. ; Ji, Chueng-Ryong ; de Melo, J. P. B. C.
Número total de Autores: 4
Tipo de documento: Artigo Científico
Fonte: PHYSICAL REVIEW D; v. 100, n. 11, p. 12-pg., 2019-12-23.
Resumo

We investigate the pion electromagnetic half-off-shell form factors, which parametrize the matrix element of the charged pion electromagnetic current with one leg off mass shell and the other leg on mass shell, using an exactly solvable manifestly covariant model of a (3 + 1)- dimensional fermion field theory. The model provides a three-dimensional imaging of the two off-shell pion form factors F-1 and F-2 as a function of (Q(2), t), which are related to each other, satisfying the Ward-Takahashi identity. The normalization of the renormalized charge form factor F-1 is fixed by F-1 (Q(2) = 0, t = m(pi)(2)) = 1, while the other form factor F-2 vanishes; i.e., F-2 (Q(2), t = = 0 for any value of Q(2) due to the time-reversal invariance of the strong interaction. We define the new form factor g(Q(2), t) = F-2 (Q(2), t)/(t - m(pi)(2)) and find that g(Q(2), t) can be measurable in the on-mass-shell limit. In particular, g(Q(2) = 0, t = m(pi)(2)) is related with the pion charge radius. We also compare our form factors with the data extracted from the pion clectroproduction reaction for both the off-shell region (t < 0) and the on-shell limit (t -> m(pi)(2)). (AU)

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
Processo FAPESP: 13/26258-4 - Matéria superdensa no universo
Beneficiário:Manuel Máximo Bastos Malheiro de Oliveira
Modalidade de apoio: Auxílio à Pesquisa - Temático
Processo FAPESP: 19/02923-5 - Física hadrônica no formalismo da frente de luz
Beneficiário:Joao Pacheco Bicudo Cabral de Mello
Modalidade de apoio: Auxílio à Pesquisa - Regular