19,399 research outputs found
Compensating linkage for main rotor control
A compensating linkage for the rotor control system on rotary wing aircraft is described. The main rotor and transmission are isolated from the airframe structure by clastic suspension. The compensating linkage prevents unwanted signal inputs to the rotor control system caused by relative motion of the airframe structure and the main rotor and transmission
Physics Potential of a 2540 Km Baseline Superbeam Experiment
We study the physics potential of a neutrino superbeam experiment with a 2540
km baseline. We assume a neutrino beam similar to the NuMI beam in medium
energy configuration. We consider a 100 kton totally active scintillator
detector at a 7 mr off-axis location. We find that such a configuration has
outstanding hierarchy discriminating capability. In conjunction with the data
from the present reactor neutrino experiments, it can determine the neutrino
mass hierarchy at 3 sigma level in less than 5 years, if sin^2(2*theta13) >
0.01, running in the neutrino mode alone. As a stand alone experiment, with a 5
year neutrino run and a 5 year anti-neutrino run, it can determine non-zero
theta13 at 3 sigma level if sin^2(2*theta13) > 7*10^{-3} and hierarchy at 3
sigma level if sin^2(2*theta13) > 8*10^{-3}. This data can also distinguish
deltaCP = pi/2 from the CP conserving values of 0 and pi, for sin^2(2*theta13)
> 0.02.Comment: 16 pages, 7 figures and 1 table: Published versio
Resolving Octant Degeneracy at LBL experiment by combining Daya Bay Reactor Setup
Long baseline Experiment (LBL) have promised to be a very powerful
experimental set up to study various issues related to Neutrinos. Some ongoing
and planned LBL and medium baseline experiments are - T2K, MINOS, NOvA, LBNE,
LBNO etc. But the long baseline experiments are crippled due to presence of
some parameter degeneracies, like the Octant degeneracy. In this work, we first
show the presence of Octant degeneracy in LBL experiments, and then combine it
with Daya Bay Reactor experiment, at different values of CP violation phase. We
show that the Octant degeneracy in LBNE can be resolved completely with this
proposal.Comment: 4 pages, 8 figure
Superconducting atomic contacts under microwave irradiation
We have measured the effect of microwave irradiation on the dc
current-voltage characteristics of superconducting atomic contacts. The
interaction of the external field with the ac supercurrents leads to replicas
of the supercurrent peak, the well known Shapiro resonances. The observation of
supplementary fractional resonances for contacts containing highly transmitting
conduction channels reveals their non-sinusoidal current-phase relation. The
resonances sit on a background current which is itself deeply modified, as a
result of photon assisted multiple Andreev reflections. The results provide
firm support for the full quantum theory of transport between two
superconductors based on the concept of Andreev bound states
Recent developments in radiative B decays
We report on recent theoretical progress in radiative B decays. We focus on a
calculation of logarithmically enhanced QED corrections to the branching ratio
and forward-backward asymmetry in the inclusive rare decay anti-B --> X(s) l+
l-, and present the results of a detailed phenomenological analysis. We also
report on the calculation of NNLO QCD corrections to the inclusive decay anti-B
--> X(s) gamma. As far as exclusive modes are concerned we consider
transversity amplitudes and the impact of right-handed currents in the
exclusive anti-B --> K^* l+ l- decay. Finally, we state results for exclusive B
--> V gamma decays, notably the time-dependent CP-asymmetry in the exclusive B
--> K^* gamma decay and its potential to serve as a so-called ``null test'' of
the Standard Model, and the extraction of CKM and unitarity triangle parameters
from B --> (rho,omega) gamma and B --> K^* gamma decays.Comment: 5 pages, 2 figures. Accepted for publication in the proceedings of
International Europhysics Conference on High Energy Physics (EPS-HEP2007),
Manchester, England, 19-25 Jul 200
Multi-component symmetry-projected approach for molecular ground state correlations
The symmetry-projected Hartree--Fock ansatz for the electronic structure
problem can efficiently account for static correlation in molecules, yet it is
often unable to describe dynamic correlation in a balanced manner. Here, we
consider a multi-component, systematically-improvable approach, that accounts
for all ground state correlations. Our approach is based on linear combinations
of symmetry-projected configurations built out of a set of non-orthogonal,
variationally optimized determinants. The resulting wavefunction preserves the
symmetries of the original Hamiltonian even though it is written as a
superposition of deformed (broken-symmetry) determinants. We show how short
expansions of this kind can provide a very accurate description of the
electronic structure of simple chemical systems such as the nitrogen and the
water molecules, along the entire dissociation profile. In addition, we apply
this multi-component symmetry-projected approach to provide an accurate
interconversion profile among the peroxo and bis(-oxo) forms of
[CuO], comparable to other state-of-the-art quantum chemical
methods
Future Precision Neutrino Oscillation Experiments and Theoretical Implications
Future neutrino oscillation experiments will lead to precision measurements
of neutrino mass splittings and mixings. The flavour structure of the lepton
sector will therefore at some point become better known than that of the quark
sector. This article discusses the potential of future oscillation experiments
on the basis of detailed simulations with an emphasis on experiments which can
be done in about ten years. In addition, some theoretical implications for
neutrino mass models will be briefly discussed.Comment: Talk given at Nobel Symposium 2004: Neutrino Physics, Haga Slott,
Enkoping, Sweden, 19-24 Aug 200
Untangling CP Violation and the Mass Hierarchy in Long Baseline Experiments
In the overlap region, for the normal and inverted hierarchies, of the
neutrino-antineutrino bi-probability space for appearance,
we derive a simple identity between the solutions in the (, ) plane for the different hierarchies. The
parameter sets the scale of the
appearance probabilities at the atmospheric eV whereas controls the amount of CP
violation in the lepton sector. The identity between the solutions is that the
difference in the values of for the two hierarchies equals twice
the value of divided by the {\it critical} value
of . We apply this identity to the two proposed
long baseline experiments, T2K and NOA, and we show how it can be used to
provide a simple understanding of when and why fake solutions are excluded when
two or more experiments are combined. The identity demonstrates the true
complimentarity of T2K and NOA.Comment: 15 pages, Latex, 4 postscript figures. Submitted to New Journal of
Physics, ``Focus on Neutrino Physics'' issu
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