16,492 research outputs found
Identifying Sneutrino Dark Matter: Interplay between the LHC and Direct Search
Under R-parity, the lightest supersymmetric particle (LSP) is stable and may
serve as a good dark matter candidate. The R-parity can be naturally introduced
with a gauge origin at TeV scale. We go over why a TeV scale B-L gauge
extension of the minimal supersymmetric standard model (MSSM) is one of the
most natural, if not demanded, low energy supersymmetric models. In the
presence of a TeV scale Abelian gauge symmetry, the (predominantly)
right-handed sneutrino LSP can be a good dark matter candidate. Its
identification at the LHC is challenging because it does not carry any standard
model charge. We show how we can use the correlation between the LHC
experiments (dilepton resonance signals) and the direct dark matter search
experiments (such as CDMS and XENON) to identify the right-handed sneutrino LSP
dark matter in the B-L extended MSSM.Comment: 5 pages, 3 figure
U(1) Gauge Theory of the Hubbard Model : Spin Liquid States and Possible Application to k-(BEDT-TTF)_2 Cu_2 (CN)_3
We formulate a U(1) gauge theory of the Hubbard model in the slave-rotor
representation. From this formalism it is argued that spin liquid phases may
exist near the Mott transition in the Hubbard model on triangular and honeycomb
lattices at half filling. The organic compound k-(BEDT-TTF)_2 Cu_2 (CN)_3 is a
good candidate for the spin liquid state on a triangular lattice. We predict a
highly unusual temperature dependence for the thermal conductivity of this
material.Comment: 5 pages, 2 figures; paper shortened and the phase diagram of
anisotropic triangular lattice correcte
Low-temperature ion beam mixing of Pt and Si markers in Ge
The mixing of Pt and Si marker atoms in Ge during 750-keV Xe irradiation was measured at temperatures between 6 and 500 K. The low-temperature measurements show that the mixing parameter for Pt is nearly twice that for Si. This result is in strong contradiction to the collisional theory of ion beam mixing. A weak temperature dependence in the mixing is found for both markers
Emergence of supersymmetry on the surface of three dimensional topological insulators
We propose two possible experimental realizations of a 2+1 dimensional
spacetime supersymmetry at a quantum critical point on the surface of three
dimensional topological insulators. The quantum critical point between the
semi-metallic state with one Dirac fermion and the s-wave superconducting state
on the surface is described by a supersymmetric conformal field theory within
-expansion. We predict the exact voltage dependence of the
differential conductance at the supersymmetric critical point.Comment: 8 pages, 2 figures; published versio
Do Library Fines Work? Analysis of the Effectiveness of Fines on Patron's Return Behavior at Two Mid-sized Academic Libraries
Data on library fines imposed at Eastern Illinois University and the University of Hawaii at Manoa was extracted and compared to determine whether fines had an impact on the patron's return behavior. The results indicated that fines as well as patron group status (undergraduate, graduate, faculty) have an impact on the patron's return behavior
Surface-Enhanced Plasmon Splitting in a Liquid-Crystal-Coated Gold Nanoparticle
We show that, when a gold nanoparticle is coated by a thin layer of nematic
liquid crystal, the deformation produced by the nanoparticle surface can
enhance the splitting of the nanoparticle surface plasmon. We consider three
plausible liquid crystal director configurations in zero electric field: boojum
pair (north-south pole configuration), baseball (tetrahedral), and homogeneous.
From a calculation using the Discrete Dipole Approximation, we find that the
surface plasmon splitting is largest for the boojum pair, intermediate for the
homogeneous, and smallest for the baseball configuration. The boojum pair
results are in good agreement with experiment. We conclude that the
nanoparticle surface has a strong effect on the director orientation, but,
surprisingly, that this deformation can actually enhance the surface plasmon
splitting.Comment: 5 pages, 3 figures To be published in PR
Coarse-grained computations of demixing in dense gas-fluidized beds
We use an "equation-free", coarse-grained computational approach to
accelerate molecular dynamics-based computations of demixing (segregation) of
dissimilar particles subject to an upward gas flow (gas-fluidized beds). We
explore the coarse-grained dynamics of these phenomena in gently fluidized beds
of solid mixtures of different densities, typically a slow process for which
reasonable continuum models are currently unavailable
Discrete Symmetries on the Light Front and a General Relation Connecting Nucleon Electric Dipole and Anomalous Magnetic Moments
We consider the electric dipole form factor, F_3(q^2), as well as the Dirac
and Pauli form factors, F_1(q^2) and F_2(q^2), of the nucleon in the
light-front formalism. We derive an exact formula for F_3(q^2) to complement
those known for F_1(q^2) and F_2(q^2). We derive the light-front representation
of the discrete symmetry transformations and show that time-reversal- and
parity-odd effects are captured by phases in the light-front wave functions. We
thus determine that the contributions to F_2(q^2) and F_3(q^2), Fock state by
Fock state, are related, independent of the fundamental mechanism through which
CP violation is generated. Our relation is not specific to the nucleon, but,
rather, is true of spin-1/2 systems in general, be they lepton or baryon. The
empirical values of the anomalous magnetic moments, in concert with empirical
bounds on the associated electric dipole moments, can better constrain theories
of CP violation. In particular, we find that the neutron and proton electric
dipole moments echo the isospin structure of the anomalous magnetic moments,
kappa^n ~ - kappa^p.Comment: 25 pages, 1 figure. Published version. Ref. adde
Patterns of Striped order in the Classical Lattice Coulomb Gas
We obtain via Monte Carlo simulations the low temperature charge
configurations in the lattice Coulomb gas on square lattices for charge filling
ratio in the range . We find a simple regularity in the low
temperature charge configurations which consist of a suitable periodic
combination of a few basic striped patterns characterized by the existence of
partially filled diagonal channels. In general there exist two separate
transitions where the lower temperature transition () corresponds to the
freezing of charges within the partially filled channels. is found to be
sensitively dependent on through the charge number density within the channels.Comment: 4 pages, 8 figure
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