38,011 research outputs found
Combined analysis of the decays and
In a combined study of the decay spectra of and
decays within a dispersive representation of the
required form factors, we illustrate how the resonance parameters,
defined through the pole position in the complex plane, can be extracted with
improved precision as compared to previous studies. While we obtain a
substantial improvement in the mass, the uncertainty in the width is only
slightly reduced, with the findings MeV and
MeV. Further constraints on the width
could result from updated analyses of the and/or spectra using
the full Belle-I data sample. Prospects for Belle-II are also discussed. As the
vector form factor enters the description of the decay , we are in a position to investigate isospin violations in its
parameters like the form factor slopes. In this respect also making available
the spectrum of the transition would be extremely
useful, as it would allow to study those isospin violations with much higher
precision.Comment: 20 pages, 1figur
Confinement of electrons in layered metals
We analyze the out of plane hopping in models of layered systems where the
in--plane properties deviate from Landau's theory of a Fermi liquid. We show
that the hopping term acquires a non trivial energy dependence, due to the
coupling to in plane excitations, and can be either relevant or irrelevant at
low energies or temperatures. The latter is always the case if the Fermi level
lies close to a saddle point in the dispersion relation.Comment: 4 pages, 1 eps figur
Suspensions Thermal Noise in the LIGO Gravitational Wave Detector
We present a calculation of the maximum sensitivity achievable by the LIGO
Gravitational wave detector in construction, due to limiting thermal noise of
its suspensions. We present a method to calculate thermal noise that allows the
prediction of the suspension thermal noise in all its 6 degrees of freedom,
from the energy dissipation due to the elasticity of the suspension wires. We
show how this approach encompasses and explains previous ways to approximate
the thermal noise limit in gravitational waver detectors. We show how this
approach can be extended to more complicated suspensions to be used in future
LIGO detectors.Comment: 28 pages, 13 figure
Cyclic homogeneous Riemannian manifolds
In spin geometry, traceless cyclic homogeneous Riemannian manifolds equipped
with a homogeneous spin structure can be viewed as the simplest manifolds after
Riemannian symmetric spin spaces. In this paper, we give some characterizations
and properties of cyclic and traceless cyclic homogeneous Riemannian manifolds
and we obtain the classification of simply-connected cyclic homogeneous
Riemannian manifolds of dimension less than or equal to four. We also present a
wide list of examples of non-compact irreducible Riemannian -symmetric
spaces admitting cyclic metrics and give the expression of these metrics
Tensorial perturbations in the bulk of inflating brane worlds
In this paper we consider the stability of some inflating brane-world models
in quantum cosmology. It is shown that whereas the singular model based on the
construction of inflating branes from Euclidean five-dimensional anti-de Sitter
space is unstable to tensorial cosmological perturbations in the bulk, the
nonsingular model which uses a five-dimensional asymptotically anti-de Sitter
wormhole to construct the inflating branes is stable to these perturbations.Comment: 4 pages, RevTex, to appear in Phys. Rev.
Homogeneous spin Riemannian manifolds with the simplest Dirac operator
We show the existence of nonsymmetric homogeneous spin Riemannian manifolds
whose Dirac operator is like that on a Riemannian symmetric spin space. Such
manifolds are exactly the homogeneous spin Riemannian manifolds which
are traceless cyclic with respect to some quotient expression and
reductive decomposition .
Using transversally symmetric fibrations of noncompact type, we give a list of
them
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