نتایج جستجو برای: bremsstrahlung imaging

تعداد نتایج: 459254  

2000
Ning Xu Long Wang Xiwei Hu

A hydrodynamic model, discussing neutral gases as well as plasmas, is applied to simulate single-bubble sonoluminescence. In this model, thermal conduction and various inelastic impact processes such as dissociation, ionization, and recombination are considered. Bremsstrahlung is assumed as the mechanism of the picosecond light pulse in sonoluminescence. Diatomic nitrogen and noble gas bubbles ...

2002
H. H. Asatryan H. M. Asatrian C. Greub M. Walker

In a recent paper [1], we presented the calculation of the O(α s) virtual corrections to b → s ℓ + ℓ − and of those bremsstrahlung terms which are needed to cancel the infrared divergences. In the present paper we work out the remaining O(α s) bremsstrahlung corrections to b → s ℓ + ℓ − , which do not suffer from infrared and collinear singularities. These new contributions turn out to be small...

1999
V. Barger T. Han C. Kao R. - J. Zhang

In the Kaluza-Klein (KK) scenario with n large extra dimensions where gravity propagates in the 4+n dimensional bulk of spacetime while gauge and matter fields are confined to a four dimensional subspace, the light graviton KK modes can be produced in the Sun, red giants and supernovae. We study the energy-loss rates through photon-photon annihilation, electron-positron annihilation, gravi-Comp...

1996
D. G. Yakovlev

Neutrino-pair bremsstrahlung radiation is considered due to electron–phonon scattering of degenerate, relativistic electrons in a lattice of spherical atomic nuclei in a neutron star crust. The neutrino energy generation rate is calculated taking into account exact spectrum of phonons, the Debye–Waller factor, and the nuclear form–factor in the density range from 10 g cm to 10 g cm at arbitrary...

2004
Sivakumar G. Manickam

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...

Journal: :Physical review letters 1996
Anthony Becker-Szendy Bosted Cavalli-Sforza Keller Kelley Klein Niemi Perl Rochester White

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...

2008
A. A. Saharian A. R. Mkrtchyan

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...

Journal: :Physical review letters 2008
Zhe Xu Carsten Greiner

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=...

1994
Kingman Cheung

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 ...

1999
J. I. KAPUSTA S. M. H. WONG

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...

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