51 research outputs found
Fermion Electric Dipole Moments in Supersymmetric Models with R-parity Violation
We analyze the electron and neutron electric dipole moments induced by
R-parity violating interactions in supersymmetric models. It is pointed out
that dominant contributions can come from one-loop diagrams involving both the
bilinear and trilinear R-parity odd couplings, leading to somewhat severe
constraints on the products of those couplings.Comment: Revtex, 19pp, four figures in axodraw.st
A Supersymmetric Theory of Flavor and R Parity
We construct a renormalizable, supersymmetric theory of flavor and parity
based on the discrete flavor group . The model can account for all the
masses and mixing angles of the Standard Model, while maintaining sufficient
squark degeneracy to circumvent the supersymmetric flavor problem. By starting
with a simpler set of flavor symmetry breaking fields than we have suggested
previously, we construct an economical Froggatt-Nielsen sector that generates
the desired elements of the fermion Yukawa matrices. With the particle content
above the flavor scale completely specified, we show that all renormalizable
-parity-violating interactions involving the ordinary matter fields are
forbidden by the flavor symmetry. Thus, parity arises as an accidental
symmetry in our model. Planck-suppressed operators that violate parity, if
present, can be rendered harmless by taking the flavor scale to be GeV.Comment: 28 pp. LaTeX, 1 Postscript Figur
Electron quantum metamaterials in van der Waals heterostructures
In recent decades, scientists have developed the means to engineer synthetic
periodic arrays with feature sizes below the wavelength of light. When such
features are appropriately structured, electromagnetic radiation can be
manipulated in unusual ways, resulting in optical metamaterials whose function
is directly controlled through nanoscale structure. Nature, too, has adopted
such techniques -- for example in the unique coloring of butterfly wings -- to
manipulate photons as they propagate through nanoscale periodic assemblies. In
this Perspective, we highlight the intriguing potential of designer
sub-electron wavelength (as well as wavelength-scale) structuring of electronic
matter, which affords a new range of synthetic quantum metamaterials with
unconventional responses. Driven by experimental developments in stacking
atomically layered heterostructures -- e.g., mechanical pick-up/transfer
assembly -- atomic scale registrations and structures can be readily tuned over
distances smaller than characteristic electronic length-scales (such as
electron wavelength, screening length, and electron mean free path). Yet
electronic metamaterials promise far richer categories of behavior than those
found in conventional optical metamaterial technologies. This is because unlike
photons that scarcely interact with each other, electrons in subwavelength
structured metamaterials are charged, and strongly interact. As a result, an
enormous variety of emergent phenomena can be expected, and radically new
classes of interacting quantum metamaterials designed
Supersymmetric Froggatt-Nielsen Models with Baryon- and Lepton-Number Violation
We systematically investigate the embedding of U(1)_X Froggatt-Nielsen models
in (four-dimensional) local supersymmetry. We restrict ourselves to models with
a single flavon field. We do not impose a discrete symmetry by hand, e.g.
R-parity, baryon-parity or lepton-parity. Thus we determine the order of
magnitude of the baryon- and/or lepton violating coupling constants through the
Froggatt-Nielsen mechanism. We then scrutinize whether the predicted coupling
constants are in accord with weak or GUT scale constraints. Many models turn
out to be incompatible.Comment: Final version, references added, minor corrections; LaTeX, 46 page
Supersymmetry without R-Parity and without Lepton Number
We investigate Supersymmetric models where neither R parity nor lepton number
is imposed. Neutrino masses can be kept highly suppressed compared to the
electroweak scale if the -terms in the superpotential are aligned with the
SUSY-breaking bilinear -terms. This situation arises naturally in the
framework of horizontal symmetries. The same symmetries suppress the trilinear
R parity violating terms in the superpotential to an acceptable level.Comment: 18 pages, harvma
The role of simulation in developing communication and gestural skills in medical students
Flavour Structure of R-violating Neutralino Decays at the LHC
We study signatures of R-parity violation in the production of supersymmetric
particles at the LHC, and the subsequent decay of the lightest neutralino being
the end product of a supersymmetric cascade decay. In doing so, we pay
particular attention to the possible flavour structure of the operators, and
how one may discriminate between different possibilities. A neutralino LSP
would couple to all quarks and leptons and a comparative study of its decays
provides an optimal channel for the simultaneous study of all 45 R-violating
operators. By studying the expected signals from all these operators, we
demonstrate the ability to understand whether more than one coupling dominates,
and to map the experimental signatures to operator hierarchies that can then be
compared against theoretical models of flavour. Detailed comparisons with
backgrounds, including those from MSSM cascade decays are made, using the
PYTHIA event simulator.Comment: 47 pages, 22 figures; v2 matches JHEP versio
On Predicting lung cancer subtypes using ‘omic’ data from tumor and tumor-adjacent histologically-normal tissue
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