1,174 research outputs found
Metastable supersymmetry breaking and multitrace deformations of SQCD
Metastable vacua in supersymmetric QCD in the presence of single and
multitrace deformations of the superpotential are explored, with the aim of
obtaining an acceptable phenomenology. The metastable vacua appear at one loop,
have a broken R-symmetry, and a magnetic gauge group that is completely
Higgsed. With only a single trace deformation, the adjoint fermions from the
meson superfield are approximately massless at one loop, even though they are
massive at tree level and R-symmetry is broken. Consequently, if charged under
the standard model, they are unacceptably light. A multitrace quadratic
deformation generates fermion masses proportional to the deformation parameter.
Phenomenologically viable models of direct gauge mediation can then be
obtained, and some of their features are discussed.Comment: 33 pages, 3 figures. Added references and a commen
Bounds on Cross-sections and Lifetimes for Dark Matter Annihilation and Decay into Charged Leptons from Gamma-ray Observations of Dwarf Galaxies
We provide conservative bounds on the dark matter cross-section and lifetime
from final state radiation produced by annihilation or decay into charged
leptons, either directly or via an intermediate particle . Our analysis
utilizes the experimental gamma-ray flux upper limits from four Milky Way dwarf
satellites: HESS observations of Sagittarius and VERITAS observations of Draco,
Ursa Minor, and Willman 1. Using 90% confidence level lower limits on the
integrals over the dark matter distributions, we find that these constraints
are largely unable to rule out dark matter annihilations or decays as an
explanation of the PAMELA and ATIC/PPB-BETS excesses. However, if there is an
additional Sommerfeld enhancement in dwarfs, which have a velocity dispersion
~10 to 20 times lower than that of the local Galactic halo, then the
cross-sections for dark matter annihilating through 's required to
explain the excesses are very close to the cross-section upper bounds from
Willman 1. Dark matter annihilation directly into 's is also marginally
ruled out by Willman 1 as an explanation of the excesses, and the required
cross-section is only a factor of a few below the upper bound from Draco.
Finally, we make predictions for the gamma-ray flux expected from the dwarf
galaxy Segue 1 for the Fermi Gamma-ray Space Telescope. We find that for a
sizeable fraction of the parameter space in which dark matter annihilation into
charged leptons explains the PAMELA excess, Fermi has good prospects for
detecting a gamma-ray signal from Segue 1 after one year of observation.Comment: 11 pages, 4 figures. References added. Final published versio
Atomic-scale coexistence of short-range magnetic order and superconductivity in FeSeTe
The ground state of the parent compounds of many high temperature
superconductors is an antiferromagnetically (AFM) ordered phase, where
superconductivity emerges when the AFM phase transition is suppressed by doping
or application of pressure. This behaviour implies a close relation between the
two orders. Understanding the interplay between them promises a better
understanding of how the superconducting condensate forms from the AFM ordered
background. Here we explore this relation in real space at the atomic scale
using low temperature spin-polarized scanning tunneling microscopy (SP-STM) and
spectroscopy. We investigate the transition from antiferromagnetically ordered
via the spin glass phase in
to superconducting
. In
we observe an
atomic-scale coexistence of superconductivity and short-ranged bicollinear
antiferromagnetic order.Comment: 7 pages, 6 figure
Searching for super-WIMPs in leptonic heavy meson decays
We study constraints on the models of bosonic super-weakly interacting
particle (super-WIMP) dark matter (DM) with DM masses keV from leptonic decays , where
is a heavy meson state. We focus on two cases where
denotes either a light pseudoscalar (axion-like), or a light vector state
that couples to the standard model (SM) through kinetic mixing. We note that
for a small DM mass these decays are separately sensitive to DM couplings to
quarks, but not its mass.Comment: 17 pages, 3 figures, 6 table
Abdominaler Schmerz
Zusammenfassung: Abdominalschmerzen können Ausdruck einer Vielzahl intra- und extraabdomineller Erkrankungen sein. Angesichts dieses breiten ätiologischen Spektrums gilt es, im Initialstadium der Diagnostik zielgerichtet vorzugehen, um ohne Zeitverzug die Ursache und damit letzlich die Dringlichkeit weitergehender Maßnahmen zu bestimmen. Ziel dieser Evaluation ist eine initiale risikostratifizierte Triagierung des Patienten. Im Gegensatz zu somatischen Ursachen abdominalen Schmerzes ist eine derartige kausale Therapie bei funktionellen Erkrankungen des Gastrointestinaltraktes zum gegenwärtigen Zeitpunkt nur sehr begrenzt möglich, sodass hierbei der Fokus auf eine bedarfs- und symptomadaptierte Behandlung gelegt werden sol
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