1,097 research outputs found
A condition on the chiral symmetry breaking solution of the Dyson-Schwinger equation in three-dimensional QED
In three-dimensional QED, which is analyzed in the 1/ expansion, we obtain
a sufficient and necessary condition for a nontrivial solution of the
Dyson-Schwinger equation to be chiral symmetry breaking solution. In the
derivation, a normalization condition of the Goldstone bound state is used. It
is showed that the existent analytical solutions satisfy this condition.Comment: 11 pages, Latex, no figures, accepted by Phys.Lett.
Breaking Discrete Symmetries in Broken Gauge Theories
We study the spontaneous breaking of discrete symmetries in theories with
broken gauge symmetry. The intended application is to CP breaking in theories
with gauged flavor symmetries, but the analysis described here is preliminary.
We dispense with matter fields and take the gauge theory to be weakly coupled
and broken spontaneously by unspecified, short-distance forces. We develop an
effective-field-theory description of the resultant low energy theory, and ask
whether this theory by itself can describe the subsequent breaking of discrete
symmetries. We conclude that this can happen depending on the parameters of the
effective theory, and that the intrinsic violation is naturally of order unity.Comment: 9 pages, 1 figure, corrected typos, added a referenc
SU(3) Family Gauge Symmetry and the Axion
We analyze the structure of a recently proposed effective field theory (EFT)
for the generation of quark and lepton mass ratios and mixing angles, based on
the spontaneous breaking of an SU(3) family gauge symmetry at a high scale F.
We classify the Yukawa operators necessary to seed the masses, making use of
the continuous global symmetries that they preserve. One global U(1), in
addition to baryon number and electroweak hypercharge, remains unbroken after
the inclusion of all operators required by standard-model-fermion
phenomenology. An associated vacuum symmetry insures the vanishing of the
first-family quark and charged-lepton masses in the absence of the family gauge
interaction. If this U(1) symmetry is taken to be exact in the EFT, broken
explicitly by only the QCD-induced anomaly, and if the breaking scale F is
taken to lie in the range 10 to 9 - 10 to 12 GeV, then the associated
Nambu-Goldstone boson is a potential QCD axion.Comment: References added and clarifications in Vacuum Structure sectio
Neutrinos and SU(3) Family Gauge Symmetry
We include the standard-model (SM) leptons in a recently proposed framework
for the generation of quark mass ratios and Cabibbo-Kobayashi-Maskawa (CKM)
mixing angles from an SU(3) family gauge interaction. The set of SM-singlet
scalar fields describing the spontaneous breaking is the same as employed for
the quark sector. The imposition at tree-level of the experimentally correct
Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix, in the form of a tri-bi
maximal structure, fixes several of the otherwise free parameters and renders
the model predictive. The normal hierarchy among the neutrino masses emerges
from this scheme.Comment: 9 pages, 3 tables; a comment added to clarify the effects of
additional Yukawa operators; final version in PR
The Electroweak Chiral Lagrangian and CP-Violating Effects in Technicolor Theories
We estimate the CP-violating and anomalous form factors,
arising from CP-violating interactions in extended technicolor theories, and
discuss their future experimental detectability. The electric dipole moment of
the boson is found to be as large as {\cal O}(10^{-21}) \; \mbox{e cm}.
We connect the CP-odd and couplings to the corresponding
CP-violating electroweak chiral lagrangian operators. The electric dipole
moments of the neutron and the electron in technicolor theories are estimated
to be as large as {\cal O}(10^{-26}) \; \mbox{e cm} and {\cal O}(10^{-29})
\; \mbox{e cm} respectively. We also suggest the potential to observe large
CP-violating technicolor effects in the decay .Comment: 34 pages, YCTP-P9-94, LaTex. (minor changes in wording and notation,
the figures are appended at the end as one postscript file
Fermion Masses and Mixing in Extended Technicolor Models
We study fermion masses and mixing angles, including the generation of a
seesaw mechanism for the neutrinos, in extended technicolor (ETC) theories. We
formulate an approach to these problems that relies on assigning right-handed
quarks and charged leptons to ETC representations that are conjugates
of those of the corresponding left-handed fermions. This leads to a natural
suppression of these masses relative to the quarks, as well as the
generation of quark mixing angles, both long-standing challenges for ETC
theories. Standard-model-singlet neutrinos are assigned to ETC representations
that provide a similar suppression of neutrino Dirac masses, as well as the
possibility of a realistic seesaw mechanism with no mass scale above the
highest ETC scale of roughly TeV. A simple model based on the ETC group
SU(5) is constructed and analyzed. This model leads to non-trivial, but not
realistic mixing angles in the quark and lepton sectors. It can also produce
sufficiently light neutrinos, although not simultaneously with a realistic
quark spectrum. We discuss several aspects of the phenomenology of this class
of models.Comment: 74 pages, revtex with embedded figure
Generalized BRST Quantization and Massive Vector Fields
A previously proposed generalized BRST quantization on inner product spaces
for second class constraints is further developed through applications. This
BRST method involves a conserved generalized BRST charge Q which is not
nilpotent but which satisfies Q=\delta+\delta^{\dagger}, \delta^2=0, and by
means of which physical states are obtained from the projection
\delta|ph>=\delta^{\dagger}|ph>=0. A simple model is analyzed in detail from
which some basic properties and necessary ingredients are extracted. The method
is then applied to a massive vector field. An effective theory is derived which
is close to the one of the Stueckelberg model. However, since the scalar field
here is introduced in order to have inner product solutions, a massive
Yang-Mills theory with polynomial interaction terms might be possible to
construct.Comment: 19 pages,Latexfil
The Perturbative Pole Mass in QCD
It is widely believed that the pole mass of a quark is infrared-finite and
gauge-independent to all orders in perturbation theory. This seems not to have
been proved in the literature. A proof is provided here.Comment: 12 pages REVTeX with 2 figures; archiving published version with note
and references added. If you thought this was proven long ago see
http://www-theory.fnal.gov/people/ask/TeX/mPole
Fermionic effective action and the pahse estructure of non compact quantum electrodynamics in 2+1 dimensions
We study the phase diagram of non compact using the microcanonical
fermionic average method described elsewhere. We present evidence for a
continuous phase transition line in the plane, extending down to
arbitrarily small flavour number .Comment: 12 pags + 1 table + 5 figs; Ref: DFTUZ 93.0
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