5,461 research outputs found
Prospects of Detecting Massive Charged Higgs from Hadronic Decay H -> tb in CMS
The possibility to detect the massive charged Higgs boson H using the
hadronic decay channel H -> tb in the associated production pp -> tH + X in the
CMS experiment at LHC is studied. There is a large background from ttbb events
which makes the observation difficult. Detection of a Higgs signal in this
channel requires an excellent b-tagging performance. Good calorimeter mass
resolution is also necessary for the full event reconstruction.Comment: 13 pages, 18 figure
The yoga of commutators
In the present paper we discuss some recent versions of localisation methods
for calculations in the groups of points of algebraic-like and classical-like
groups. Namely, we describe relative localisation, universal localisation, and
enhanced versions of localisation-completion. Apart from the general strategic
description of these methods, we state some typical technical results of the
conjugation calculus and the commutator calculus. Also, we state several recent
results obtained therewith, such as relative standard commutator formulae,
bounded width of commutators, with respect to the elementary generators, and
nilpotent filtrations of congruence subgroups. Overall, this shows that
localisation methods can be much more efficient, than expected
Renormalized non-modal theory of the kinetic drift instability of plasma shear flows
The linear and renormalized nonlinear kinetic theory of drift instability of
plasma shear flow across the magnetic field, which has the Kelvin's method of
shearing modes or so-called non-modal approach as its foundation, is developed.
The developed theory proves that the time-dependent effect of the finite ion
Larmor radius is the key effect, which is responsible for the suppression of
drift turbulence in an inhomogeneous electric field. This effect leads to the
non-modal decrease of the frequency and growth rate of the unstable drift
perturbations with time. We find that turbulent scattering of the ion gyrophase
is the dominant effect, which determines extremely rapid suppression of drift
turbulence in shear flow
Langmuir wave linear evolution in inhomogeneous nonstationary anisotropic plasma
Equations describing the linear evolution of a non-dissipative Langmuir wave
in inhomogeneous nonstationary anisotropic plasma without magnetic field are
derived in the geometrical optics approximation. A continuity equation is
obtained for the wave action density, and the conditions for the action
conservation are formulated. In homogeneous plasma, the wave field E
universally scales with the electron density N as E ~ N^{3/4}, whereas the
wavevector evolution varies depending on the wave geometry
Evidence for two-gap nodeless superconductivity in SmFeAsOF from point-contact Andreev-reflection spectroscopy
Point-contact Andreev-reflection measurements were performed in
SmFeAsO_{0.8}F_{0.2} polycrystals with T_c \simeq 53 K. The experimental
conductance curves reproducibly exhibit peaks around \pm 6 mV and shoulders at
V \sim 16-20 mV, indicating the presence of two nodeless superconducting gaps.
While the single-band Blonder-Tinkham-Klapwijk fit can only reproduce a small
central portion of the conductance curve, the two-gap one accounts remarkably
well for the shape of the whole experimental dI/dV. The fits of the normalized
curves give Delta_1(0) = 6.15 \pm 0.45 meV and Delta_2(0) = 18 \pm 3 meV. Both
gaps close at the same temperature and follow a BCS-like behavior.Comment: 4 pages, 4 eps color figure
Experimental and Numerical Investigation of Near-field Rotor Aeroacoustics
This work presents comparisons between experimental and numerical estimates of near-field rotor
aeroacoustics in hover. The experiments took place at the Kazan National Research Technical University
named after A. N. Tupolev (Kazan Aviation Institute). A set of rotor blades with NACA-0012 aerofoil sections
was used to obtain the sound pressure distribution using a linear array of microphones. It is shown that CFD
and experimental results are in good agreement suggesting that the obtained test data can be useful as a
validation case for development of CFD tools
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