We consider the resummation of large electroweak Sudakov logarithms for annihilation neutralino DM with $\mathcal{O}$(TeV) mass to high-energy photons in minimal supersymmetric standard model, extending previous work on wino and Higgsino models. find that NLL reduces yield by about $20\%$ Higgsino-dominated at masses around 1~TeV, up $45\%$ neutralinos larger admixture heavier near 3~TeV. This ...

We study large- p_T pT three-photon production at the LHC center-of-mass energy \sqrt{s}=8 display="inline">s=8 TeV. use LO approximation of parton Reg...

The propagation of photons, electrons and positrons at ultra-high energies above ∼ 10 eV can be changed considerably if the dispersion relations of these particles are modified by terms suppressed by powers of the Planck scale. We recently pointed out that the current non-observation of photons in the ultra-high energy cosmic ray flux at such energies can put strong constraints on such modified...

In the proposed E-166 experiment at SLAC, 50 GeV electrons pass through a helical undulator, and produce circularly polarized photons, which interact with a tungsten target and generate longitudinally polarized positrons. The background is an important issue for an experiment under consideration. To address this issue, simulations were performed with the code GEANT3 to model the production of s...

We have calculated the opacities and secondary production mechanisms of high energy photons arising in gamma-ray burst internal shocks, using exact cross-sections for the relevant processes. We find that for reasonable choices of parameters, photons in the range of 10's to 100's of GeV may be emitted in the prompt phase. Photons above this range are subject to electron-positron pair production ...

In radionuclide treatment, tumor cells are primarily destroyed by charged particles emitted by the compound while associated higher energy photons are used to image the tumor in order to determine radiation dose and monitor shrinkage. However, the higher energy photons are difficult to image with conventional collimated Anger cameras, since a tradeoff exists between resolution and sensitivity, ...