2,404 research outputs found

### Revisiting Critical Vortices in Three-Dimensional SQED

We consider renormalization of the central charge and the mass of the ${\cal
N}=2$ supersymmetric Abelian vortices in 2+1 dimensions. We obtain ${\cal N}=2$
supersymmetric theory in 2+1 dimensions by dimensionally reducing the ${\cal
N}=1$ SQED in 3+1 dimensions with two chiral fields carrying opposite charges.
Then we introduce a mass for one of the matter multiplets without breaking N=2
supersymmetry. This massive multiplet is viewed as a regulator in the large
mass limit. We show that the mass and the central charge of the vortex get the
same nonvanishing quantum corrections, which preserves BPS saturation at the
quantum level. Comparison with the operator form of the central extension
exhibits fractionalization of a global U(1) charge; it becomes 1/2 for the
minimal vortex. The very fact of the mass and charge renormalization is due to
a "reflection" of an unbalanced number of the fermion and boson zero modes on
the vortex in the regulator sector.Comment: 24 pages, 2 figures Minor modifications, reference adde

### Conformal Windows of SU(N) Gauge Theories, Higher Dimensional Representations and The Size of The Unparticle World

We present the conformal windows of SU(N) supersymmetric and
nonsupersymmetric gauge theories with vector-like matter transforming according
to higher irreducible representations of the gauge group. We determine the
fraction of asymptotically free theories expected to develop an infrared fixed
point and find that it does not depend on the specific choice of the
representation. This result is exact in supersymmetric theories while it is an
approximate one in the nonsupersymmetric case. The analysis allows us to size
the unparticle world related to the existence of underlying gauge theories
developing an infrared stable fixed point. We find that exactly 50 % of the
asymptotically free theories can develop an infrared fixed point while for the
nonsupersymmetric theories it is circa 25 %. When considering multiple
representations, only for the nonsupersymmetric case, the conformal regions
quickly dominate over the nonconformal ones. For four representations, 70 % of
the asymptotically free space is filled by the conformal region.
According to our theoretical landscape survey the unparticle physics world
occupies a sizable amount of the particle world, at least in theory space, and
before mixing it (at the operator level) with the nonconformal one.Comment: RevTeX, 18 pages, 2 figure

### A Chiral SU(N) Gauge Theory Planar Equivalent to Super-Yang-Mills

We consider the dynamics of a strongly coupled SU(N) chiral gauge theory. By
using its large-N equivalence with N=1 super-Yang-Mills theory we find the
vacuum structure of the former. We also consider its finite-N dynamics.Comment: 10 pages, Latex. 1 eps figur

### Semi-direct Gauge Mediation in Conformal Windows of Vector-like Gauge Theories

Direct gauge mediation models using the Intriligator-Seiberg-Shih (ISS)
metastable vacua suffer from the Landau pole problem of the standard model
gauge couplings and the existence of R symmetry forbidding gaugino masses.
These problems may be solved by using the recently proposed SUSY breaking
models in a conformal window of the vector-like $SU(N_C)$ gauge theory with
gauge singlets. In this paper we propose a model of gauge mediation based on
the SUSY-breaking model in the conformal window, and study the dynamics for the
SUSY breaking. In the model, there are massive vector-like bifundamental fields
charged under both $SU(N_C)$ and the standard model gauge group, and our model
can be regarded as a semi-direct gauge mediation model. The color number $N_C$
can be small to avoid the Landau pole problem, and the R symmetry is also
broken under a reasonable assumption on the strong dynamics of the model. The
model possesses only one free parameter, and the gaugino and sfermion masses
are naturally of the same order.Comment: 21 pages, 1 figur

### Enhanced di-Higgs Production through Light Colored Scalars

We demonstrate enhanced di-Higgs production at the LHC in the presence of
modifications of the effective couplings of Higgs to gluons from new, light,
colored scalars. While our results apply to an arbitrary set of colored
scalars, we illustrate the effects with a real color octet scalar -- a simple,
experimentally viable model involving a light (~125-300 GeV) colored scalar.
Given the recent LHC results, we consider two distinct scenarios: First, if the
Higgs is indeed near 125 GeV, we show that the di-Higgs cross section could be
up to nearly one thousand times the Standard Model rate for particular octet
couplings and masses. This is potentially observable in \emph{single} Higgs
production modes, such as $pp \to h h \to \gamma\gamma b\bar{b}$ as well as $pp
\to h h \to \tau^+\tau^- b\bar{b}$ where a small fraction of the $\gamma\gamma$
or $\tau^+\tau^-$ events near the putative Higgs invariant mass peak contain
also a $b\bar{b}$ resonance consistent with the Higgs mass. Second, if the
Higgs is not at 125 GeV (and what the LHC has observed is an impostor), we show
that the same parameter region where singly-produced Higgs production can be
suppressed below current LHC limits, for a heavier Higgs mass, also
simultaneously predicts substantially enhanced di-Higgs production. We point
out several characteristic signals of di-Higgs production with a heavier Higgs
boson, such as $pp \to hh \to W^+W^-W^+W^-$, which could use same-sign
dileptons or trileptons plus missing energy to uncover evidence.Comment: 13 pages, 8 figure

### Supersymmetry Inspired QCD Beta Function

We propose an all orders beta function for ordinary Yang-Mills theories with
or without fermions inspired by the Novikov-Shifman-Vainshtein-Zakharov beta
function of N=1 supersymmetric gauge theories. The beta function allows us to
bound the conformal window. When restricting to one adjoint Weyl fermion we
show how the proposed beta function matches the one of supersymmetric
Yang-Mills theory. The running of the pure Yang-Mills coupling is computed and
the deviation from the two loop result is presented. We then compare the
deviation with the one obtained from lattice data also with respect to the two
loop running.Comment: 17 pages and 3 figures. References Adde

### From Super-Yang-Mills Theory to QCD: Planar Equivalence and its Implications

We review and extend our recent work on the planar (large N) equivalence
between gauge theories with varying degree of supersymmetry. The main emphasis
is made on the planar equivalence between N=1 gluodynamics (super-Yang-Mills
theory) and a non-supersymmetric "orientifold field theory." We outline an
"orientifold" large N expansion, analyze its possible phenomenological
consequences in one-flavor massless QCD, and make a first attempt at extending
the correspondence to three massless flavors. An analytic calculation of the
quark condensate in one-flavor QCD starting from the gluino condensate in N=1
gluodynamics is thoroughly discussed. We also comment on a planar equivalence
involving N=2 supersymmetry, on "chiral rings" in non-supersymmetric theories,
and on the origin of planar equivalence from an underlying, non-tachyonic
type-0 string theory. Finally, possible further directions of investigation,
such as the gauge/gravity correspondence in large-N orientifold field theory,
are briefly discussed.Comment: 106 pages, LaTex. 15 figures. v2:minor changes, refs. added. To be
published in the Ian Kogan Memorial Collection "From Fields to Strings:
Circumnavigating Theoretical Physics," World Scientific, 200

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