Petr Beneš (Řež):
Dynamical breakdown of Abelian gauge chiral symmetry by strong Yukawa interactions
Abstract:
We consider a model with anomalyfree Abelian gauge
axialvector symmetry, which is intended to mimic the standard electroweak gauge
chiral SU(2)_{L} x U(1)_{Y} theory. Within this model we demonstrate:
(1) Strong Yukawa interactions
between massless fermion fields and a massive scalar field carrying the axial charge generate dynamically
the fermion and boson proper selfenergies, which are ultravioletfinite and chirally noninvariant.
(2) Solutions of the underlying SchwingerDyson equations found numerically exhibit a huge amplification
of the fermion mass ratios as a response to mild changes of the ratios of the Yukawa couplings.
(3) The `wouldbe' NambuGoldstone boson is a composite of both the fermion and scalar fields, and it
gives rise to the mass of the axialvector gauge boson. (4) Spontaneous breakdown of the gauge
symmetry further manifests by mass splitting of the complex scalar and by new symmetrybreaking
vertices, generated at one loop. In particular, we work out in detail the cubic vertex of the Abelian
gauge boson.
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