The modelling of ortho-positronium annihilation processes in nanoporous humidity-sensitive ceramics were performed using the Tao-Eldrup model. It is shown that this model is adequate for modelling “pick-off” annihilation processes in ceramic materials for sensors applications and calculation of the size of their nanopores.

We calculate the production cross sections for D∗+D∗−, D+D∗− and D+D− in e+e− annihilation through one virtual photon in the framework of perturbative QCD with constituent quarks. The calculated cross sections for D∗+D∗− and D+D∗− production are roughly in agreement with the recent Belle data. The helicity decomposition for D ∗ meson production is also calculated. The fraction of the D L D ∗∓ T...

We model the annihilation of relic positrons produced in a gamma-ray burst (GRB) after its afterglow has faded. We find that the annihilation signal from at least one GRB remnant in the Milky Way galaxy should be observable with future space missions such as INTEGRAL and EXIST, provided that the gas surrounding the GRB source has the typical density of the interstellar medium, ∼< 1 cm . Three f...

We study in detail the ability of the nominal configuration of the IceCube neutrino telescope (with 80 strings) to probe the parameter space of the Constrained MSSM (CMSSM) favoured by current collider and cosmological data. Adopting conservative assumptions about the galactic halo model and the expected experiment performance, we find that IceCube has a probability between 2% and 12% of achiev...

The mean-field reaction-diffusion equations of the diffusive pair-annihilation and triplett-annihilation processes are considered. A direct lower bound on the time-dependent mean particle-density is derived. The results are applied to the mean-field theory of the diffusive pair-contact process. PACS numbers: 05.10.Gg, 05.70.ln, 02.30.Jr Laboratoire associé au CNRS UMR 7556 permanent address

The possibility is examined for the inclusive Λ in unpolarized electron-positron annihilation to be transversely polarized. Due to final-state interactions, there exists a novel structure function F̂ (z,Q) for the inclusive Λ hyperon (or any other baryons) production from the unpolarized time-like photon fragmentation, which makes contribution to the transverse Λ polarization in the unpolarized ...

We calculate, in a systematic way, the enhancement effect on p̄p and p̄A annihilation cross sections at low energy due to the initial state electrostatic interaction between the projectile and the target nucleus. This calculation is aimed at future comparisons between n̄ and p̄ annihilation rates on different targets, for the extraction of pure isospin channels.

The principle of image formation in tomography is summarised. The principle ofpositron electron annihilation is introduced. The principle of coincidence techniques is illustrated. Detector development and perspectives for positron emission tomography (PET) instrumentation for medical research is presented. The physical processes in in positron annihilation, photon scattering and tomograph desig...

The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) has been observing gammaray lines from the Sun and the Galaxy since its launch in February 2002. Here I summarize the status of RHESSI observations of solar lines (nuclear de-excitation, neutron capture, and positron annihilation), the lines of Al and Fe from the inner Galaxy, and the search for positron annihilation in novae.

A short review of theoretical and experimental results on fragmentation in e + e − annihilation is presented. Starting with an introduction of the concept of fragmentation functions in e + e − annihilation, aspects of scaling violation, multiplicities, small and large x, longitudinal, gluon, light and heavy quark fragmentation are summarized.