https://doi.org/10.1140/epja/s10050-025-01620-7
Regular Article - Theoretical Physics
Symmetry breaking effects in pion couplings to constituent quark currents
Instituto de Física, Federal University of Goias, Av. Esperança, s/n, 74690-900, Goiânia, GO, Brazil
Received:
13
March
2025
Accepted:
15
June
2025
Published online:
4
July
2025
Pseudoscalar and axial neutral and charged pion-constituent quark coupling constants are investigated with nondegenerate quark masses in different kinematical points, off shell and on shell pions and constituent quarks. By considering a large quark mass expansion of a quark determinant in the presence of local pion field and of constituent quark background currents, gluonic effects are considered by means of an effective gluon propagator that dresses quark currents. For the neutral pion, mixing effects are introduced by means of the pion mixing to states 
and 
, that give rise to the 
meson mixing, and mixing of quark currents via corresponding mixing interactions. The relative behavior of charged and neutral pion coupling constants to quarks may be nearly the same—in the framework of the constituent quark model—as the pion–nucleon coupling constants if mixings are introduced. A very small pion coupling to strange quark current is also obtained. The dependence of the positive and negative pion-constituent quark coupling constant on the non-degeneracy of quark masses, for emission and absorption processes, is identified.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
