15,691 research outputs found
Precise Predictions for Higgs Production in Neutralino Decays in the Complex MSSM
Complete one-loop results are obtained for the class of processes
chi^0_i->chi^0_j h_a in the MSSM where all parameters entering this process
beyond lowest order are allowed to have arbitrary CP-violating phases. An
on-shell renormalisation scheme is worked out for the chargino-neutralino
sector that properly takes account of imaginary parts arising from complex
parameters and from absorptive parts of loop integrals. The genuine vertex
contributions to the neutralino decay amplitudes are combined with two-loop
propagator-type corrections for the outgoing Higgs boson. In this way the
currently most precise prediction for this class of processes is obtained. The
numerical impact of the genuine vertex corrections is studied for several
examples of CP-conserving and CP-violating scenarios. We find that significant
effects on the decay widths and branching ratios are possible even in the
CP-conserving MSSM. In the CP-violating CPX benchmark scenario the corrections
to the decay width are found to be particularly large, namely, of order 45% for
a Higgs mass of 40 GeV. This parameter region of the CPX scenario where a very
light Higgs boson is unexcluded by present data is analysed in detail. We find
that in this parameter region, which will be difficult to cover by standard
Higgs search channels at the LHC, the branching ratio for the decay
chi^0_2->chi^0_1 h_1 is large. This may offer good prospects to detect such a
light Higgs boson in cascade decays of supersymmetric particles.Comment: 24 pages, 6 figure
Testing and evaluation of solid lubricants for gas bearings
The testing and results of testing solid film lubricants for gas lubricated bearing applications are reported. The tests simulated operational hazards of tilting pad gas bearings. The presence of a low coefficient of friction and the endurance of the solid film lubricant were the criteria for judging superior performance. All solid lubricants tested were applied to a plasma sprayed chrome oxide surface. Molybdenum disulfide and graphite fluoride were the solid lubricants tested; other test parameters included the method of application of the solid lubricant and the surface finish of the plasma sprayed coating. In general, the application of a solid film lubricant was found to significantly improve the coefficient of friction of the rubbing surfaces
White primer permits a corrosion-resistant coating of minimum weight
White primer for coating 2219 aluminum alloy supplies a base for a top coating of enamel. A formulation of pigments and vehicle results in a primer with high corrosion resistance and minimum film thickness
Are the reactions a challenge for the factorized Pomeron at high energies?
We would like to point to the strong violation of the putative factorized
Pomeron exchange model in the reactions in the
high-energy region where this model works fairly well in all other cases.Comment: 4 pages, LaTex, 1 fig. in postscript, minor typos corrected, to be
published in Phys. Rev. D 60, 117503 (1999
Curvature Constraints from the Causal Entropic Principle
Current cosmological observations indicate a preference for a cosmological
constant that is drastically smaller than what can be explained by conventional
particle physics. The Causal Entropic Principle (Bousso, {\it et al}.) provides
an alternative approach to anthropic attempts to predict our observed value of
the cosmological constant by calculating the entropy created within a causal
diamond. We have extended this work to use the Causal Entropic Principle to
predict the preferred curvature within the "multiverse". We have found that
values larger than are disfavored by more than 99.99% and a
peak value at and
for open universes. For universes that allow only positive curvature or both
positive and negative curvature, we find a correlation between curvature and
dark energy that leads to an extended region of preferred values. Our universe
is found to be disfavored to an extent depending the priors on curvature. We
also provide a comparison to previous anthropic constraints on open universes
and discuss future directions for this work.Comment: 5 pages, 3 Figure
Development of corrosion inhibiting white primer final report, 26 jun. - 30 nov. 1964
Corrosion resisting white prime
Survival curves and age response functions for chinese hamster cells exposed to X-rays or high LET alpha-particles
Varying c cosmology and Planck value constraints
It has been suggested that by increasing the speed of light during the early
universe various cosmological problems of standard big bang cosmology can be
overcome, without requiring an inflationary phase. However, we find that as the
Planck length and Planck time are then made correspondingly smaller, and
together with the need that the universe should not re-enter a Planck epoch,
the higher models have very limited ability to resolve such problems. For a
constantly decreasing the universe will quickly becomes quantum
gravitationally dominated as time increases: the opposite to standard cosmology
where quantum behaviour is only ascribed to early times.Comment: extended versio
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