34,896 research outputs found
A simple model of gauged lepton and baryon charges
We argue that simpler fermionic contents, responsible for the extension of
the standard model with gauged lepton and baryon charges, can be constructed by
assuming existence of so-called leptoquarks (j,k) with exotic electric charges
q_j=1/2, q_k=-1/2. Some new features in our model are that (i) as the natural
consequences of anomaly cancelation the right-handed neutrinos exist, and the
number of the observed fermion families is equal to the number of the
fundamental colors; (ii) although the lepton and baryon charges are conserved,
the neutrinos can obtain small masses through the type I seesaw mechanism in
similarity to the standard context, and the baryogenesis can be generated in
several cases. They all are natural results due to the spontaneous breaking of
these charges. Some constraints on the new physics via flavor changing and
related phenomenologies such as the stable scalar with anomalous electric
charge and interested processes at colliders are also discussed.Comment: 13 pages, revised versio
Improving Stochastic Estimator Techniques for Disconnected Diagrams
Disconnected diagrams are expected to be sensitive to the inclusion of
dynamical fermions. We present a feasibility study for the observation of such
effects on the nucleonic matrix elements of the axial vector current, using
SESAM full QCD vacuum configurations with Wilson fermions on
lattices, at . Starting from the standard methods developed by the
Kentucky and Tsukuba groups, we investigate the improvement from various
refinements thereof.Comment: One author added. Contribution to Lattice 1997, 3 pages LaTex, to
appear in Nucl. Phys. B (Proc. Suppl.
Question of Peccei-Quinn symmetry and quark masses in the economical 3-3-1 model
We show that there is an infinite number of U(1) symmetries like Peccei-Quinn
symmetry in the 3-3-1 model with minimal scalar sector---two scalar triplets.
Moreover, all of them are completely broken due to the model's scalars by
themselves (notice that these scalars as known have been often used to break
the gauge symmetry and generating the masses for the model's particles). There
is no any residual Peccei-Quinn symmetry. Because of the minimal scalar content
there are some quarks that are massless at tree-level, but they can get
consistent mass contributions at one-loop due to this fact. Interestingly,
axions as associated with the mentioned U(1)s breaking (including Majoron due
to lepton-charge breaking) are all gauged away because they are also the
Goldstone bosons responsible for the gauge symmetry breaking as usual.Comment: 25 pages, 4 figures, revised version, to appear in Physical Review
On Representations of Conformal Field Theories and the Construction of Orbifolds
We consider representations of meromorphic bosonic chiral conformal field
theories, and demonstrate that such a representation is completely specified by
a state within the theory. The necessary and sufficient conditions upon this
state are derived, and, because of their form, we show that we may extend the
representation to a representation of a suitable larger conformal field theory.
In particular, we apply this procedure to the lattice (FKS) conformal field
theories, and deduce that Dong's proof of the uniqueness of the twisted
representation for the reflection-twisted projection of the Leech lattice
conformal field theory generalises to an arbitrary even (self-dual) lattice. As
a consequence, we see that the reflection-twisted lattice theories of Dolan et
al are truly self-dual, extending the analogies with the theories of lattices
and codes which were being pursued. Some comments are also made on the general
concept of the definition of an orbifold of a conformal field theory in
relation to this point of view.Comment: 11 pages, LaTeX. Updated references and added preprint n
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