We perform stability analysis of an accretion disc around a stellar mass black hole. The cooling of the accretion flow due to bremsstrahlung and synchrotron radiation processes are considered. The solutions with shock are perturbed at the shock location and the radial dependence of perturbation is obtained by solving the equations numerically using fourth-order Runge-Kutta method. The perturbat...

In 1953, Ter-Mikaelian predicted that the bremsstrahlung of low energy pho-tons in a medium is suppressed because of interactions between the produced photon and the electrons in the medium. This suppression occurs because the emission takes place over on a long distance scale, allowing for destructive interference between diierent instantaneous photon emission amplitudes. We present here measu...

We investigate the coherent bremsstrahlung by relativistic electrons in a single crystal excited by hypersonic vibrations. The formula for the corresponding differential cross-section is derived in the case of a sinusoidal wave. The conditions are specified under which the influence of the hypersound is essential. The case is considered in detail when the electron enters into the crystal at sma...

The relation of the shear viscosity coefficient to the recently introduced transport rate is derived within relativistic kinetic theory. We calculate the shear viscosity over entropy ratio eta/s for a gluon gas, which involves elastic gg-->gg perturbative QCD (PQCD) scatterings as well as inelastic gg<-->ggg PQCD bremsstrahlung. For alpha_{s}=0.3 we find eta/s=0.13 and for alpha_{s}=0.6, eta/s=...

We present the photoproduction of an intermediate mass Higgs (IMH) boson associated with a W boson at the future electron-proton colliders using bremsstrahlung photon beam or laser backscattered photon beam. With bremsstrahlung photon beam the search for the IMH boson is unfavorable because of the small signal rate. But with laser photon beam the search is viable due to a much larger rate, and ...

We examine the bremsstrahlung photons emitted in the central collisions of two gold nuclei at the Relativistic Heavy Ion Collider. While the measurements of the final hadrons can reveal only the amount of stopping, they tell us very little about the space-time evolution of the bulk matter in the collisions. By using two extreme collision scenarios, we argue that the low and medium energy bremss...

We report the results of a new calculation of soft-gluon corrections in B → Xsll decays. In particular, we present the first calculation of bremsstrahlung and corresponding virtual terms to the lepton forward–backward asymmetry, which allows us to systematically include all contributions to this observable beyond the lowest non-trivial order. The new terms are important, for instance the positi...

It is well known that beamstrahlung and bremsstrahlung take place over a finite formation zone distance. If something disturbs the electron during this time, the emission can be suppressed. In this paper, we examine the Landau-PomeranchukMigdal (LPM) effect and other LPM-like effects, such as the longitudinal density (dielectric) suppression and EM field suppression of beamstrahlungand bremsstr...

Most calculations of air shower development have been based on the Bethe-Heitler cross sections for bremsstrahlung and pair production. However, for energetic enough particles, a number of different external factors can reduce these cross sections drastically, slowing shower development and lengthening the showers. Four mechanisms that can suppress bremsstrahlung and pair production cross secti...

In the present paper we investigate coherent bremsstrahlung of high energy electrons moving in a periodically deformed single crystal with a complex base. The formula for corresponding differential cross-section is derived for an arbitrary deformation field. The conditions are discussed under which the influence of the deformation is important. The case is considered in detail when the electron...