99 research outputs found
A Pure-Glue Hidden Valley I. States and Decays
It is possible that the standard model is coupled, through new massive
charged or colored particles, to a hidden sector whose low energy dynamics is
controlled by a pure Yang-Mills theory, with no light matter. Such a sector
would have numerous metastable "hidden glueballs" built from the hidden gluons.
These states would decay to particles of the standard model. We consider the
phenomenology of this scenario, and find formulas for the lifetimes and
branching ratios of the most important of these states. The dominant decays are
to two standard model gauge bosons, or by radiative decays with photon
emission, leading to jet- and photon-rich signals.Comment: 34 pages, 4 figure
The Higgs as a Portal to Plasmon-like Unparticle Excitations
A renormalizable coupling between the Higgs and a scalar unparticle operator
O_U of non-integer dimension d_U<2 triggers, after electroweak symmetry
breaking, an infrared divergent vacuum expectation value for O_U. Such IR
divergence should be tamed before any phenomenological implications of the
Higgs-unparticle interplay can be drawn. In this paper we present a novel
mechanism to cure that IR divergence through (scale-invariant) unparticle
self-interactions, which has properties qualitatively different from the
mechanism considered previously. Besides finding a mass gap in the unparticle
continuum we also find an unparticle pole reminiscent of a plasmon resonance.
Such unparticle features could be explored experimentally through their mixing
with the Higgs boson.Comment: 12 LaTeX pages, 2 figure
Duality of Sp(2N) and SO(N) Supersymmetric Gauge Theories with Adjoint Matter
We discuss electric-magnetic duality in two new classes of supersymmetric
Yang-Mills theories. The models have gauge group Sp(2\nc) or SO(\nc) with
matter in both the adjoint and defining representations. By perturbing these
theories with various superpotentials, we find a variety of new infrared fixed
points with dual descriptions. This work is complementary to that of Kutasov
and Schwimmer on SU(\nc) and of Intriligator on other models involving
Sp(2\nc) and SO(\nc).Comment: 14 pages, no figures, uses harvma
Phase Transitions of Orientifold Gauge Theories at Large N in Finite Volume
In this paper we consider the phase structure of ``orientifold'' gauge
theories--obtained from unitary supersymmetric gauge theories by replacing
adjoint Majorana fermions by Dirac fermions in the symmetric or anti-symmetric
representations--in finite volume S^3 x S^1. If the radius of the S^3 is small
the calculations can be performed at weak coupling for any value of the S^1
radius. We demonstrate that there is a confinement/de-confining type of phase
transition even when the fermions have periodic (non-thermal) boundary
conditions around S^1. At small radius of S^1, the theory is in a phase where
charge conjugation and large non-periodic gauge transformation are
spontaneously broken. But for large radius of S^1 the phase preseves these
symmetries just as in the related supersymmetric theory.Comment: 12 page
QCD String as Vortex String in Seiberg-Dual Theory
We construct a classical vortex string solution in a Seiberg-dual theory of
N=1 supersymmetric SO(N_c) QCD which flows to a confining phase. We claim that
this vortex string is a QCD string, as previouly argued by M.Strassler. In
SO(N_c) QCD, it is known that stable QCD strings exist even in the presence of
dynamical quarks. We show that our vortex strings are stable in the
Seiberg-dual theory.Comment: 15 pages, 1 figur
Relations between some analytic representations of one-loop scalar integrals
We compare several parametrized analytic expressions for an arbitrary
off-shell one-loop -point function in scalar field theory in -dimensional
space-time, and show their equivalence both directly and through path-integral
methods.Comment: 12 pages, NIKHEF-H/94-2
Folded Supersymmetry and the LEP Paradox
We present a new class of models that stabilize the weak scale against
radiative corrections up to scales of order 5 TeV without large corrections to
precision electroweak observables. In these `folded supersymmetric' theories
the one loop quadratic divergences of the Standard Model Higgs field are
cancelled by opposite spin partners, but the gauge quantum numbers of these new
particles are in general different from those of the conventional
superpartners. This class of models is built around the correspondence that
exists in the large N limit between the correlation functions of supersymmetric
theories and those of their non-supersymmetric orbifold daughters. By
identifying the mechanism which underlies the cancellation of one loop
quadratic divergences in these theories, we are able to construct simple
extensions of the Standard Model which are radiatively stable at one loop.
Ultraviolet completions of these theories can be obtained by imposing suitable
boundary conditions on an appropriate supersymmetric higher dimensional theory
compactified down to four dimensions. We construct a specific model based on
these ideas which stabilizes the weak scale up to about 20 TeV and where the
states which cancel the top loop are scalars not charged under Standard Model
color. Its collider signatures are distinct from conventional supersymmetric
theories and include characteristic events with hard leptons and missing
energy.Comment: 18 pages, 5 figures, references correcte
Proposal for Higgs and Superpartner Searches at the LHCb Experiment
The spectrum of supersymmetric theories with R-parity violation are much more
weakly constrained than that of supersymmetric theories with a stable
neutralino. We investigate the signatures of supersymmetry at the LHCb
experiment in the region of parameter space where the neutralino decay leaves a
displaced vertex. We find sensitivity to squark production up to squark masses
of order 1 TeV. We note that if the Higgs decays to neutralinos in this
scenario, LHCb should see the lightest Higgs boson before ATLAS and CMS.Comment: 7 pages, 5 figure
Necessary and sufficient conditions for non-perturbative equivalences of large N orbifold gauge theories
Large N coherent state methods are used to study the relation between U(N)
gauge theories containing adjoint representation matter fields and their
orbifold projections. The classical dynamical systems which reproduce the large
N limits of the quantum dynamics in parent and daughter orbifold theories are
compared. We demonstrate that the large N dynamics of the parent theory,
restricted to the subspace invariant under the orbifold projection symmetry,
and the large N dynamics of the daughter theory, restricted to the untwisted
sector invariant under "theory space'' permutations, coincide. This implies
equality, in the large N limit, between appropriately identified connected
correlation functions in parent and daughter theories, provided the orbifold
projection symmetry is not spontaneously broken in the parent theory and the
theory space permutation symmetry is not spontaneously broken in the daughter.
The necessity of these symmetry realization conditions for the validity of the
large N equivalence is unsurprising, but demonstrating the sufficiency of these
conditions is new. This work extends an earlier proof of non-perturbative large
N equivalence which was only valid in the phase of the (lattice regularized)
theories continuously connected to large mass and strong coupling.Comment: 21 page, JHEP styl
Duality and Dynamical Supersymmetry Breaking in with a Spinor
We study supersymmetric chiral gauge theories with a
single spinor representation and vector representations. We present a dual
description in terms of an supersymmetric chiral gauge
theory with a symmetric tensor, one fundamental and antifundamental
representations. The theory with breaks supersymmetry at
strong coupling; we study how this arises at weak coupling in the dual theory,
which is a spontaneously broken gauge theory. Also, we recover various known
dualities, find new dual pairs and generate new examples of dynamical
supersymmetry breaking.Comment: 9 pages, uses harvmac, no figur
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