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 $\phi$. 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 $\phi$'s required to explain the excesses are very close to the cross-section upper bounds from Willman 1. Dark matter annihilation directly into $\tau$'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

β-Amyloid (1–42) Levels in Cerebrospinal Fluid and Cerebral Atrophy in Mild Cognitive Impairment and Alzheimer's Disease

Background: Recent studies consistently reported Alzheimer’s disease (AD) and, to a lower extent, mild cognitive impairment (MCI) to be accompanied by reduced cerebrospinal fluid (CSF) levels of β-amyloid. However, how these changes are related to brain morphological alterations is so far only partly understood. Methods: CSF levels of β-amyloid (1–42) were examined with respect to cerebral atrophy in 23 subjects with MCI, 16 patients with mild-to-moderateAlzheimer’s disease (AD) and 15 age-matched controls by using magnetic resonance imaging and voxel-based morphometry (VBM). Results: When contrasted with the controls, β-amyloid (1–42) levels were significantly lower (p Conclusion: Our finding confirms the results of previous studies and suggests that both the decrease in β-amyloid (1–42) and the development of hippocampal atrophy coincide in the disease process

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 $m_X \sim \mathcal{O}(1 - 100)$ keV from leptonic decays $M\rightarrow \ell \bar{\nu}_\ell + X$, where $M=B^\pm, D^\pm, D_s^\pm$ is a heavy meson state. We focus on two cases where $X$ 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

Two Loop R-Symmetry Breaking

We analyze two loop quantum corrections for pseudomoduli in O'Raifeartaigh like models. We argue that R-symmetry can be spontaneously broken at two loop in non supersymmetric vacua. We provide a basic example with this property. We discuss on phenomenological applications.Comment: 13 pages, 5 figures, JHEP3.cls, reference adde

Surveying Pseudomoduli: the Good, the Bad and the Incalculable

We classify possible types of pseudomoduli which arise when supersymmetry is dynamically broken in infrared-free low-energy theories. We show that, even if the pseudomoduli potential is generated only at higher loops, there is a regime where the potential can be simply determined from a combination of one-loop running data. In this regime, we compute whether the potential for the various types of pseudomoduli is safe, has a dangerous runaway to the UV cutoff of the low-energy theory, or is incalculable. Our results are applicable to building new models of supersymmetry breaking. We apply the results to survey large classes of models.Comment: 34 page