8,811 research outputs found
No radiative generation of Chern-Simons-like term in Lorentz-violating QED: dealing with IR divergences
The issue intensively claimed in the literature on the generation of a
CPT-odd and Lorentz violating Chern-Simons-like term by radiative corrections
owing to a CPT violating interaction -- the axial coupling of fermions with a
constant vector field b_\m -- is mistaken. The presence of massless gauge
field triggers IR divergences that might show up from the UV subtractions,
therefore, so as to deal with the (actual physical) IR divergences, the
Lowenstein-Zimmermann subtraction scheme, in the framework of BPHZL
renormalization method, has to be adopted. The proof on the non generation of
such a Chern-Simons-like term is done, independent of any kind of
regularization scheme, at all orders in perturbation theory.Comment: In honor of Prof. Manfred Schweda (1939-2017). Work presented at the
XXXVIII National Meeting on Particle Physics and Fields, September 18-22,
2017 - Passa Quatro - Minas Gerais - Brazil. Reference [46] correcte
No parity anomaly in massless QED3: a BPHZL approach
In this letter we call into question the perturbatively parity breakdown at
1-loop for the massless QED_3 frequently claimed in the literature. As long as
perturbative quantum field theory is concerned, whether a parity anomaly owing
to radiative corrections exists or not will be definitely proved by using a
renormalization method independent of any regularization scheme. Such a problem
has been investigated in the framework of BPHZL renormalization method, by
adopting the Lowenstein-Zimmermann subtraction scheme. The 1-loop parity-odd
contribution to the vacuum-polarization tensor is explicitly computed in the
framework of the BPHZL renormalization method. It is shown that a Chern-Simons
term is generated at that order induced through the infrared subtractions --
which violate parity. We show then that, what is called parity anomaly, is in
fact a parity-odd counterterm needed for restauring parity.Comment: 4 pages, no figures, to appear in Physics Letters
An algebraic proof on the finiteness of Yang-Mills-Chern-Simons theory in D=3
A rigorous algebraic proof of the full finiteness in all orders of
perturbation theory is given for the Yang-Mills-Chern-Simons theory in a
general three-dimensional Riemannian manifold. We show the validity of a trace
identity, playing the role of a local form of the Callan-Symanzik equation, in
all loop orders, which yields the vanishing of the beta-functions associated to
the topological mass and gauge coupling constant as well as the anomalous
dimensions of the fields.Comment: 5 pages, revte
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