2,398 research outputs found
Gauge-Higgs unification on the brane
From the quantum field theory point of view, matter and gauge fields are
generally expected to be localised around branes or topological defects
occurring in extra dimensions. Here I discuss a simple scenario where, by
starting with a five dimensional SU(3) gauge theory, we end up with several 4-D
parallel branes with localised "chiral" fermions and gauge fields to them. I
will show that it is possible to reproduce the electroweak model confined to a
single brane, allowing a simple and geometrical approach to the fermion
hierarchy problem. Some nice results of this construction are: Gauge and Higgs
fields are unified at the 5-D level; and new particles are predicted: a
left-handed neutrino of zero hypercharge, and a massive vector field coupling
together the new neutrino to other left-handed leptons.Comment: Contribution to the proceedings of the RTN workshop "The Quest for
Unification: Theory Confronts Experiment", Corfu, Greece, Sept 11-18, 200
Cosmological attractors in massive gravity
We study Lorentz-violating models of massive gravity which preserve rotations
and are invariant under time-dependent shifts of the spatial coordinates. In
the linear approximation the Newtonian potential in these models has an extra
``confining'' term proportional to the distance from the source. We argue that
during cosmological expansion the Universe may be driven to an attractor point
with larger symmetry which includes particular simultaneous dilatations of time
and space coordinates. The confining term in the potential vanishes as one
approaches the attractor. In the vicinity of the attractor the extra
contribution is present in the Friedmann equation which, in a certain range of
parameters, gives rise to the cosmic acceleration.Comment: 26 pages, 1 figur
Towards common origin of supersymmetry breaking, compositeness, and gauge mediation
We present a toy model which has the following properties: i) it is strongly
coupled at a certain scale and breaks supersymmetry at this scale; ii) matter
superfields of (one generation of) the Standard Model are effective low energy
degrees of freedom of this strongly coupled theory; iii) direct gauge mediation
of supersymmetry breaking occurs due to messenger superfields that are also
effective low energy degrees of freedom. We discuss the way to generalize this
approach to realistic models with three generations. These models might be
favorable from the point of view of string theory compactifications.Comment: 7 pages, LaTeX, no figures; grant numbers correcte
Gauge theory solitons on noncommutative cylinder
We generalize to noncommutative cylinder the solution generation technique,
originally suggested for gauge theories on noncommutative plane. For this
purpose we construct partial isometry operators and complete set of orthogonal
projectors in the algebra of the cylinder, and an isomorphism between the free
module and its direct sum with the Fock module on the cylinder. We construct
explicitly the gauge theory soliton and evaluate the spectrum of perturbations
about this soliton.Comment: References added; to appear in Theor.Math.Phy
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