Annihilation of the electron-positron pairs (or (e−, e)−pairs, for short) in various polyelectrons e n e− m = e− m e n (where n ≥ 1 and m ≥ 1) is considered. In particular, we discuss the threeand four-photon annihilation of the (e−, e)−pairs in the three-body Ps− ion and four-body bi-positronium system Ps2. It is shown that the five-body e + 2 e − 3 ion is an unbound system. The closed form ex...

We analyze the decay B → φK within the framework of QCD-improved factorization. We found that although the twist-3 kaon distribution amplitude dominates the spectator interactions, it will suppress the decay rates slightly. The weak annihilation diagrams induced by (V −A)(V +A) penguin operators, which are formally power-suppressed by order (ΛQCD/mb) 2, are chirally and in particular logarithmi...

We investigate the asymptotic properties of two reaction–diffusion systems. The first is an annihilation/scattering system with the reactions 2A → ∅, 2A → 2B, 2B → 2A, and 2B → ∅. The second one consists of competing annihilation and fission processes, 2A → ∅ and 2A → (n+2)A. We find that both these diffusion–limited reaction systems belong to the same universality class as the single species a...

We discuss the possibility of GLAST detecting gamma-rays from the annihilation of neutralino dark matter in the Galactic halo. We have used “Via Lactea”, currently the highest resolution simulation of cold dark matter substructure, to quantify the contribution of subhalos to the annihilation signal. We present a simulated allsky map of the expected gamma-ray counts from dark matter annihilation...

The electrochemistry and radical ion annihilation electrogenerated chemiluminescence (ECL) of 9,9'-spirobifluorene-bridged bipolar systems containing 1,3,4-oxadiazole-conjugated oligoaryl and triarylamine substituents were investigated. The stability of the oxidized spirobifluorenes was improved by functionalization with triarylamine centers. These donor-acceptor (DA) compounds exhibited a good...

We study the impact of the halo shape and geometry on the expected weakly interacting massive particle (WIMP) dark matter annihilation signal from the galactic center. As the halo profile in the innermost region is still poorly constrained, we focus on geometrical distortions and consider different density behaviors like flat cores, cusps and spikes. We show that asphericity has a strong impact...

We evaluate the relic density of neutralinos in the minimal supergravity (mSUGRA) model. All 2 → 2 neutralino annihilation diagrams, as well as all initial states involving sleptons, charginos, neutralinos, and third generation squarks are included. Relativistic thermal averaging of the velocity times cross sections is performed. We find that co-annihilation effects are only important on the ed...