11,293 research outputs found
Natural NMSSM with a Light Singlet Higgs and Singlino LSP
Supersymmetry (SUSY) is an attractive extension of the Standard Model (SM) of
particle physics which solves the SM hierarchy problem. Motivated by the
theoretical -term problem of the Minimal Supersymmetric Model (MSSM), the
Next-to MSSM (NMSSM) can also account for experimental deviations from the SM
like the anomalous muon magnetic moment and the dark matter relic density.
Natural SUSY, motivated by naturalness considerations, exhibits small fine
tuning and a characteristic phenomenology with light higgsinos, stops and
gluinos. We describe a scan in NMSSM parameter space motivated by Natural SUSY
and guided by the phenomenology of an NMSSM with a slightly broken Peccei-Quinn
symmetry and a lightly coupled singlet. We identify a scenario which survives
experimental constraints with a light singlet Higgs and a singlino lightest
SUSY particle. We then discuss how the scenario is not presently excluded by
searches at the Large Hadron Collider (LHC) and which channels are promising
for discovery at the LHC and International Linear Collider.Comment: Added results of checks on LHC Run 1 exclusion with CheckMAT
ATLAS Searches for Beyond the Standard Model Higgs Bosons
The present status of ATLAS searches for Higgs bosons in extensions of the
Standard Model (SM) is presented. This includes searches for the Higgs bosons
of the Two-Higgs-Doublet Model (2HDM), the Minimal Supersymmetric Model (MSSM),
the Next-to-Minimal Supersymmetric Model (NMSSM) and models with an invisibly
decaying Higgs boson. A review of the phenomenology of the Higgs sectors of
these models is given together with the search strategy and the resulting
experimental constraints.Comment: Presentation at the DPF 2013 Meeting of the American Physical Society
Division of Particles and Fields, Santa Cruz, California, August 13-17, 201
Classification of interacting electronic topological insulators in three dimensions
A fundamental open problem in condensed matter physics is how the dichotomy
between conventional and topological band insulators is modified in the
presence of strong electron interactions. We show that there are 6 new
electronic topological insulators that have no non-interacting counterpart.
Combined with the previously known band-insulators, these produce a total of 8
topologically distinct phases. Two of the new topological insulators have a
simple physical description as Mott insulators in which the electron spins form
spin analogs of the familiar topological band-insulator. The remaining are
obtained as combinations of these two `topological paramagnets' and the
topological band insulator. We prove that these 8 phases form a complete list
of all possible interacting topological insulators, and are classified by a
Z_2^3 group-structure. Experimental signatures are also discussed for these
phases.Comment: New version contains more results on experimental signatures and a
more rigorous proof of a key statement (see Appendix D,E), with references
reorganize
Zero-bias peaks in spin-orbit coupled superconducting wires with and without Majorana end-states
One of the simplest proposed experimental probes of a Majorana bound-state is
a quantized (2e^2/h) value of zero-bias tunneling conductance. When temperature
is somewhat larger than the intrinsic width of the Majorana peak, conductance
is no longer quantized, but a zero-bias peak can remain. Such a non-quantized
zero-bias peak has been recently reported for semiconducting nanowires with
proximity induced superconductivity. In this paper we analyze the relation of
the zero-bias peak to the presence of Majorana end-states, by simulating the
tunneling conductance for multi-band wires with realistic amounts of disorder.
We show that this system generically exhibits a (non-quantized) zero-bias peak
even when the wire is topologically trivial and does not possess Majorana
end-states. We make comparisons to recent experiments, and discuss the
necessary requirements for confirming the existence of a Majorana state.Comment: 5 pages, 4 Figure
A two-dimensional mixing length theory of convective transport
The helioseismic observations of the internal rotation profile of the Sun
raise questions about the two-dimensional (2D) nature of the transport of
angular momentum in stars. Here we derive a convective prescription for
axisymmetric (2D) stellar evolution models. We describe the small scale motions
by a spectrum of unstable linear modes in a Boussinesq fluid. Our saturation
prescription makes use of the angular dependence of the linear dispersion
relation to estimate the anisotropy of convective velocities. We are then able
to provide closed form expressions for the thermal and angular momentum fluxes
with only one free parameter, the mixing length.
We illustrate our prescription for slow rotation, to first order in the
rotation rate. In this limit, the thermodynamical variables are spherically
symetric, while the angular momentum depends both on radius and latitude. We
obtain a closed set of equations for stellar evolution, with a self-consistent
description for the transport of angular momentum in convective regions. We
derive the linear coefficients which link the angular momentum flux to the
rotation rate (- effect) and its gradient (-effect). We
compare our results to former relevant numerical work.Comment: MNRAS accepted, 10 pages, 1 figure, version prior to language editio
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