Anomalies in direct and indirect detection have motivated models of dark matter consisting of a multiplet of nearly-degenerate states, coupled by a new GeV-scale interaction. We perform a careful analysis of the thermal freezeout of dark matter annihilation in such a scenario. We compute the range of “boost factors” arising from Sommerfeld enhancement in the local halo for models which produce ...

We show that a class of topological field theories are quantum duals of the harmonic oscillator. This is demonstrated by establishing a correspondence between the creation and annihilation operators and non-local gauge invariant observables of the topological field theory. The example is used to discuss some issues concerning background independence and the relation of vacuum energy to the prob...

We apply the spectral method, recently developed by the authors, to calculate the statistics of a reaction-limited multistep birth-death process, or chemical reaction, that includes as elementary steps branching A-->2A and annihilation 2A-->0 . The spectral method employs the generating function technique in conjunction with the Sturm-Liouville theory of linear differential operators. We focus ...

Abstract This paper considers contact processes with additional voter model dynamics. For such models, results of Lloyd and Sudbury can be applied to find a self-duality, as well as dualities and thinning relations with systems of random walks with annihilation, branching, coalescence, and deaths. We show that similar relations, which are known from the literature for certain interacting SDE’s,...

Extended analysis of the " penguin " part of K → ππ amplitude Abstract We make an attempt to clarify the role of the annihilation or " penguin " mode in the description of the K → ππ decay within the Standard Model. The attention is concentrated on new operators in the effective ∆S = 1 Hamiltonian and the violation of factorization for mesonic matrix elements of the local four-quark operators. ...

The diffuse galactic EGRET gamma ray data show a clear excess for energies above 1 GeV in comparison with the expectations from conventional galactic models. The excess is seen with the same spectrum in all sky directions, as expected for Dark Matter (DM) annihilation. This hypothesis is investigated in detail. The energy spectrum of the excess is used to limit the WIMP mass to the 50-100 GeV r...

A generic feature of weakly interacting massive particle (WIMP) dark matter models is the emission of photons over a broad energy band resulting from the stable yields of dark matter pair annihilation. Inverse Compton scattering off cosmic microwave background photons of energetic electrons and positrons produced in dark matter annihilation is expected to produce significant diffuse X-ray emiss...

The diffuse galactic EGRET gamma ray data show a clear excess for energies above 1 GeV in comparison with the expectations from conventional galactic models. The excess is seen with the same spectrum in all sky directions, as expected for Dark Matter (DM) annihilation. This hypothesis is investigated in detail. The energy spectrum of the excess is used to limit the WIMP mass to the 50-100 GeV r...

I discuss event cuts in DIS which improve the similarity between the current Breit hemisphere and hemispheres in ee annihilation. I also present a method to study the scale evolution in quark hemispheres using data from fixed energy ee experiments. This method can benefit from the high statistics and flavour tagging at LEP1, also at scales relevant for a comparison with HERA results.

Positron annihilation was applied to measuring critical pore sizes in various materials. In recent years, positron annihilation with a variable-energy positron beam has emerged as a powerful tool for the investigation of porous thin films synthesized as low-k dielectrics, high performance gas sensor materials, and so on. This paper is a brief overview of recent progress in nanopore characteriza...