637 research outputs found
Bhabha scattering at LEP1. Calorimeter event selection
Analitical calculations have been used to describe the calorimeter event
selection in small-angle electron-positron scattering at LEP1. The first-order
QED correction to the Born cross-section has been derived with leading log and
the next-to-leading log approximations. The second- and the third-order
corrections were computed with leading accuracy. The present analytical results
are illustated by Tabeles and compared with the corresponding results obtained
with the Monte Carlo generator BHLUMI.Comment: 26p., submitted to Journ. of Physics
Stationary States in Bistable System Driven by L\'evy Noise
We study the properties of the probability density function (PDF) of a
bistable system driven by heavy tailed white symmetric L\'evy noise. The shape
of the stationary PDF is found analytically for the particular case of the
L\'evy index \alpha = 1 (Cauchy noise). For an arbitrary L\'evy index we employ
numerical methods based on the solution of the stochastic Langevin equation and
space fractional kinetic equation. In contrast with the bistable system driven
by Gaussian noise, in the L\'evy case the positions of maxima of the stationary
PDF do not coincide with the positions of minima of the bistable potential. We
provide a detailed study of the distance between the maxima and the minima as a
function of the potential's depth and L\'evy noise parameters.Comment: Accepted to EPJS
The Electron-Phonon Interaction of Low-Dimensional and Multi-Dimensional Materials from He Atom Scattering
Atom scattering is becoming recognized as a sensitive probe of the
electron-phonon interaction parameter at metal and metal-overlayer
surfaces. Here, the theory is developed linking to the thermal
attenuation of atom scattering spectra (in particular, the Debye-Waller
factor), to conducting materials of different dimensions, from quasi-one
dimensional systems such as W(110):H(11) and Bi(114), to quasi-two
dimensional layered chalcogenides and high-dimensional surfaces such as
quasicrystalline 2ML-Ba(0001)/Cu(001) and d-AlNiCo(00001). Values of
obtained using He atoms compare favorably with known values for the bulk
materials. The corresponding analysis indicates in addition the number of
layers contributing to the electron-phonon interaction that is measured in an
atom surface collision.Comment: 23 pages, 5 figures, 1 tabl
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