1,503 research outputs found
Probing neutralino dark matter in the MSSM & the NMSSM with directional detection
We investigate the capability of directional detectors to probe neutralino
dark matter in the Minimal Supersymmetric Standard Model and the
Next-to-Minimal Supersymmetric Standard Model with parameters defined at the
weak scale. We show that directional detectors such as the future MIMAC
detector will probe spin dependent dark matter scattering on nucleons that are
beyond the reach of current spin independent detectors. The complementarity
between indirect searches, in particular using gamma rays from dwarf spheroidal
galaxies, spin dependent and spin independent direct search techniques is
emphasized. We comment on the impact of the negative results on squark searches
at the LHC. Finally, we investigate how the fundamental parameters of the
models can be constrained in the event of a dark matter signal.Comment: 21 pages, 16 figure
AdS(3) Solutions of IIB Supergravity from D3-branes
We consider pure D3-brane configurations of IIB string theory which lead to
supersymmetric solutions containing an AdS factor. They can provide new
examples of AdS/CFT examples on D3-branes whose worldvolume is
partially compactified. When the internal 7 dimensional space is non-compact,
they can be identified as supersymmetric fluctuations of higher dimensional AdS
solutions and are in general dual to 1/8-BPS operators thereof. We find that
supersymmetry requires the 7 dimensional space take the form of a warped U(1)
fibration over a 6 dimensional Kahler manifold.Comment: 10 pages, no figure, JHEP3.cls; v3: corrected errors in the published
versio
M2-branes wrapped on holomorphic curves
The generalised calibration for a wrapped membrane is gauge equivalent to the
supergravity three-form under which the membrane is electrically charged. Given
the relevant calibration, one can go a long way towards constructing the
supergravity solution for the wrapped brane. Applications of this method have
been restricted since generalised calibrations have not yet been completely
classified in spacetimes with non-vanishing flux. In this paper, we take a
first step towards such a classification by studying membranes wrapping
holomorphic curves. Supersymmetry preservation imposes a constraint on the
Hermitean metric in the embedding space and it is found that this can be
expressed as a restriction on possible generalised calibrations. Allowed
calibrations in a particular spacetime are simply those which satisfy the
constraint equation relevant to that background; in particular, we see that the
previously considered Kahler calibrations are just a subclass of possible
solutions.Comment: Discussion clarified, typos corrected, references updated. Results
remain unchanged. 12 page
Charge Distributions in Metallic Alloys: a Charge Excess Functional theory approach
Charge Distributions in Metallic Alloys: a Charge Excess Functional theory
approachComment: 13 pages, 5 figure
Vertex Corrections and the Korringa Ratio in Strongly Correlated Electron Materials
We show that the Korringa ratio, associated with nuclear magnetic resonance
in metals, is unity if vertex corrections for the dynamic spin susceptibility
are negligible and the hyperfine coupling is momentum independent. In the
absence of vertex corrections we also find a Korringa behaviour for , the
nuclear spin relaxation rate, i.e., , and a temperature
independent Knight shift. These results are independent of the form and
magnitude of the self-energy (so far as is consistent with neglecting vertex
corrections) and of the dimensionality of the system.Comment: 5 pages. accepted for publication in J. Phys.: Condens. Matte
Boundary states, matrix factorisations and correlation functions for the E-models
The open string spectra of the B-type D-branes of the N=2 E-models are
calculated. Using these results we match the boundary states to the matrix
factorisations of the corresponding Landau-Ginzburg models. The identification
allows us to calculate specific terms in the effective brane superpotential of
E_6 using conformal field theory methods, thereby enabling us to test results
recently obtained in this context.Comment: 20 pages, no figure
Collective Charge Excitation in a Dimer Mott Insulating System
Charge dynamics in a dimer Mott insulating system, where a non-polar
dimer-Mott (DM) phase and a polar charge-ordered (CO) phase compete with each
other, are studied. In particular, collective charge excitations are analyzed
in the three different models where the internal-degree of freedom in a dimer
is taken into account. Collective charge excitation exists both in the
non-polar DM phase and the polar CO phase, and softens in the phase boundary.
This mode is observable by the optical conductivity spectra where the light
polarization is parallel to the electric polarization in the polar CO phase.
Connections between the present theory and the recent experimental results in
kappa-(BEDT-TTF)2Cu2(CN)3 are discussed.Comment: 5 pages, 4 figure
M-Theory solutions with AdS factors
Solutions of D=7 maximal gauged supergravity are constructed with metrics
that are a product of a n-dimensional anti-de Sitter (AdS) space, with
n=2,3,4,5, and certain Einstein manifolds. The gauge fields have the same form
as in the recently constructed solutions describing the near-horizon limits of
M5-branes wrapping supersymmetric cycles. The new solutions do not preserve any
supersymmetry and can be uplifted to obtain new solutions of D=11 supergravity,
which are warped and twisted products of the D=7 metric with a squashed
four-sphere. Some aspects of the stability of the solutions are discussed.Comment: 30 pages. References adde
Exclusion, Discovery and Identification of Dark Matter with Directional Detection
Directional detection is a promising search strategy to discover galactic
Dark Matter. We present a Bayesian analysis framework dedicated to data from
upcoming directional detectors. The interest of directional detection as a
powerful tool to set exclusion limits, to authentify a Dark Matter detection or
to constrain the Dark Matter properties, both from particle physics and
galactic halo physics, will be demonstrated.Comment: 10 pages, 11 figures; Proceedings of the 3rd International conference
on Directional Detection of Dark Matter (CYGNUS 2011), Aussois, France, 8-10
June 201
Condensation of Excitons in Cu2O at Ultracold Temperatures: Experiment and Theory
We present experiments on the luminescence of excitons confined in a
potential trap at milli-Kelvin bath temperatures under cw-excitation. They
reveal several distinct features like a kink in the dependence of the total
integrated luminescence intensity on excitation laser power and a bimodal
distribution of the spatially resolved luminescence. Furthermore, we discuss
the present state of the theoretical description of Bose-Einstein condensation
of excitons with respect to signatures of a condensate in the luminescence. The
comparison of the experimental data with theoretical results with respect to
the spatially resolved as well as the integrated luminescence intensity shows
the necessity of taking into account a Bose-Einstein condensed excitonic phase
in order to understand the behaviour of the trapped excitons.Comment: 41 pages, 23 figure
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