2,175 research outputs found
Non-Canonical MSSM, Unification, And New Particles At The LHC
We consider non-canonical embeddings of the MSSM in high-dimensional orbifold
GUTs based on the gauge symmetry SU(N), N=5,6,7,8. The hypercharge
normalization factor k_Y can either have unique non-canonical values, such as
23/21 in a six-dimensional SU(7) model, or may lie in a (continuous) interval.
Gauge coupling unification and gauge-Yukawa unification can be realized in
these models by introducing new particles with masses in the TeV range which
may be found at the LHC. In one such example there exist color singlet
fractionally charged states.Comment: 1+25 pages, 5 figures. v2: Introduction revised, sections reordered,
figure 4 correcte
Coleman-Weinberg Potential In Good Agreement With WMAP
We briefly summarize and update a class of inflationary models from the early
eighties based on a quartic (Coleman-Weinberg) potential for a gauge singlet
scalar (inflaton) field. For vacuum energy scales comparable to the grand
unification scale, the scalar spectral index n_s=0.94-0.97, in very good
agreement with the WMAP three year results. The tensor to scalar ratio r<~0.14,
while alpha=dn/dlnk is =~-10^-3. An SO(10) version naturally explains the
observed baryon asymmetry via non-thermal leptogenesis.Comment: v1: 6 pages, 1 table. v2: minor corrections. v3: 8 pages, added some
details, comments, references and 3 figures. v4: minor corrections, published
versio
Flux of Primordial Monopoles
We discuss how in supersymmetric models with D and F-flat directions, a
primordial monopole flux of order 10^{-16} - 10^{-18} cm^{-2} sec^{-1} sr^{-1}
can coexist with the observed baryon asymmetry. A modified Affleck-Dine
scenario yields the desired asymmetry if the monopoles are superheavy (~
10^{13}-10^{18} GeV). For lighter monopoles with masses ~ 10^{9}-10^{12} GeV,
the baryon asymmetry can arise via TeV scale leptogenesis.Comment: 17 pages, 4 figures, revtex
Inflation in Supersymmetric SU(5)
We analyze the adjoint field inflation in supersymmetric (SUSY) SU(5) model.
In minimal SUSY SU(5) hybrid inflation monopoles are produced at the end of
inflation. We therefore explore the non-minimal model of inflation based on
SUSY SU(5), like shifted hybrid, which provides a natural solution for the
monopole problem. We find that the supergravity corrections with non-minimal
Kahler potential are crucial to realize the central value of the scalar
spectral index n_s ~ 0.96 consistent with the seven year WMAP data. The tensor
to scalar ratio r is quite small, taking on values r < 10^{-5}. Due to
R-symmetry massless SU(3) octet and SU(2) triplet Higgs bosons are present and
could spoil for gauge coupling unification. To keep gauge coupling unification
intact, light vector-like particles are added which are expected to be observed
at LHC.Comment: 16 page
Effects of Neutrino Inverse Seesaw Mechanism on the Sparticle Spectrum in CMSSM and NUHM2
We study the implications of the inverse seesaw mechanism (ISS) on the
sparticle spectrum in the Constrained Minimal Supersymmetric Standard Model
(CMSSM) and Non-Universal Higgs Model (NUHM2). Employing the maximal value of
the Dirac Yukawa coupling involving the up type Higgs doublet provides a 2-3
GeV enhancement of the lightest CP-even Higgs boson mass. This effect permits
one to have lighter colored sparticles in the CMSSM and NUHM2 scenarios with
LSP neutralino, which can be tested at LHC14. We present a variety of LHC
testable benchmark points with the desired LSP neutralino dark matter relic
abundance.Comment: 18 pages, 10 figures and 2 table
Interference and Deployment Issues for Cognitive Radio Systems in Shadowing Environments
In this paper we describe a model for calculating the aggregate interference
encountered by primary receivers in the presence of randomly placed cognitive
radios (CRs). We show that incorporating the impact of distance attenuation and
lognormal fading on each constituent interferer in the aggregate, leads to a
composite interference that cannot be satisfactorily modeled by a lognormal.
Using the interference statistics we determine a number of key parameters
needed for the deployment of CRs. Examples of these are the exclusion zone
radius, needed to protect the primary receiver under different types of fading
environments and acceptable interference levels, and the numbers of CRs that
can be deployed. We further show that if the CRs have apriori knowledge of the
radio environment map (REM), then a much larger number of CRs can be deployed
especially in a high density environment. Given REM information, we also look
at the CR numbers achieved by two different types of techniques to process the
scheduling information.Comment: to be presented at IEEE ICC 2009. This posting is the same as the
original one. Only author's list is updated that was unfortunately not
correctly mentioned in first versio
On the Impact of Antenna Topologies for Massive MIMO Systems
Approximate expressions for the spatial correlation of cylindrical and
uniform rectangular arrays (URA) are derived using measured distributions of
angles of departure (AOD) for both the azimuth and zenith domains. We examine
massive multiple-input-multiple-output (MIMO) convergence properties of the
correlated channels by considering a number of convergence metrics. The
per-user matched filter (MF) signal-to-interference-plus-noise ratio (SINR)
performance and convergence rate, to respective limiting values, of the two
antenna topologies is also explored.Comment: 6 pages, 6 figure
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