31,845 research outputs found
Electroweak corrections to e+ e- -> nu anti-nu H and e+ e- -> t anti-t H
The most interesting Higgs-production processes at future e+ e- colliders
belong to the process class e+ e- -> f anti-f H. We study the full O(alpha)
corrections to this reaction in the Standard Model for neutrinos and top quarks
in the final state. Leading higher-order corrections from initial-state
radiation and QCD corrections are also taken into account. Although
cancellations between the different kinds of corrections occur, the full
corrections are of the order of +/-10% and thus important ingredients in the
theoretical predictions for future e+ e- colliders.Comment: 3 pages, LaTeX, 4 postscript figures, talk given at the EPS
conference, Aachen, 200
Light environment - A. Visible light. B. Ultraviolet light
Visible and ultraviolet light environment as related to human performance and safety during space mission
Electroweak radiative corrections to e+ e- -> t anti-t H
We have calculated the complete electroweak O(alpha) radiative corrections to
the Higgs-boson production process e+ e- -> t anti-t H in the electroweak
Standard Model. Initial-state radiation beyond O(alpha) is included in the
structure-function approach. The calculation of the corrections is briefly
described, and numerical results are presented for the total cross section.
Both the photonic and the genuine weak corrections reach the order of about 10%
or even more and show a non-trivial dependence on the Higgs-boson mass and on
the scattering energy. We compare our results with two previous calculations
that obtained differing results at high energies.Comment: 13 pages, LaTeX, 12 postscript figure
Comparison of Gaia and asteroseismic distances
Asteroseismology provides fundamental properties (mass, radius and effective
temperature) of solar-like oscillating stars using so-called scaling relations.
These properties allow the computation of the asteroseismic distance of stars.
We compare the asteroseismic distances with the recently released Gaia
distances for 74 stars studied in Y{\i}ld{\i}z et al. There is a very good
agreement between these two distances; for 64 of these stars, the difference is
less than 10 per cent. However, a systematic difference is seen if we use the
effective temperature obtained by spectroscopic methods; the Gaia distances are
about 5 per cent greater than the asteroseismic distances.Comment: 4 pages, 4 figures, accepted by MNRA
Depletion potentials near geometrically structured substrates
Using the recently developed so-called White Bear version of Rosenfeld's
Fundamental Measure Theory we calculate the depletion potentials between a
hard-sphere colloidal particle in a solvent of small hard spheres and simple
models of geometrically structured substrates: a right-angled wedge or edge. In
the wedge geometry, there is a strong attraction beyond the corresponding one
near a planar wall that significantly influences the structure of colloidal
suspensions in wedges. In accordance with an experimental study, for the edge
geometry we find a free energy barrier of the order of several which
repels a big colloidal particle from the edge.Comment: 7 pages, 7 figure
Solar Dynamics, Rotation, Convection and Overshoot
We discuss recent observational, theoretical and modeling progress made in
understanding the Sun's internal dynamics, including its rotation, meridional
flow, convection and overshoot. Over the past few decades, substantial
theoretical and observational effort has gone into appreciating these aspects
of solar dynamics. A review of these observations, related helioseismic
methodology and inference and computational results in relation to these
problems is undertaken here.Comment: 31 pages, 10 figures, Space Science Review
Electroweak Precision Physics at e+ e- Colliders with RacoonWW
We present precise predictions for the processes e+ e- -> WW -> 4f(gamma) at
LEP2 and future Linear-Collider (LC) energies obtained with the Monte Carlo
generator RacoonWW. The program RacoonWW includes the complete O(alpha)
electroweak radiative corrections to e+ e- -> WW -> 4f in the double-pole
approximation (DPA). While the virtual corrections are treated in DPA, the
calculation of the bremsstrahlung corrections is based on the full lowest-order
matrix elements to the processes e+ e- -> 4f+gamma. This asymmetric treatment
of virtual and real photons requires a careful matching of the arising infrared
and collinear singularities. We also take into account higher-order
initial-state photon radiation via the structure-function method. Here, we
briefly describe the RacoonWW approach, give numerical results for the total
W-pair production cross sections, confront them with LEP2 data, and study the
impact of the radiative corrections on angular and W-invariant-mass
distributions at LEP2 and LC energies.Comment: 12 pages, 13 postscript figures, to appear in the Proceedings of the
22nd annual MRST Conference on Theoretical High Energy Physics (MRST 2000),
Rochester, New York, May 8-9, 200
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