107,488 research outputs found
On the extension of 2- polynomials
Let be a three dimensional real Banach space. Ben\'itez and Otero \cite
{BeO} showed that if the unit ball of is is an intersection of two
ellipsoids, then every 2-polynomial defined in a linear subspace of can be
extended to preserving the norm. In this article, we extend this result to
any finite dimensional Banach space
A remark on contraction semigroups on Banach spaces
Let be a complex Banach space and let be a duality section
on (i.e. ). For any
unit vector and any () contraction semigroup ,
Goldstein proved that if is a Hilbert space and if as , then is an eigenvector of
corresponding to a purely imaginary eigenvalue. In this article, we prove the
similar result holds if is a strictly convex complex Banach space
Nonuniversal Effects in the Homogeneous Bose Gas
Effective field theory predicts that the leading nonuniversal effects in the
homogeneous Bose gas arise from the effective range for S-wave scattering and
from an effective three-body contact interaction. We calculate the leading
nonuniversal contributions to the energy density and condensate fraction and
compare the predictions with results from diffusion Monte Carlo calculations by
Giorgini, Boronat, and Casulleras. We give a crude determination of the
strength of the three-body contact interaction for various model potentials.
Accurate determinations could be obtained from diffusion Monte Carlo
calculations of the energy density with higher statistics.Comment: 24 pages, RevTex, 5 ps figures, included with epsf.te
Probing annihilations and decays of low-mass galactic dark matter in IceCube DeepCore array: Track events
The deployment of DeepCore array significantly lowers IceCube's energy
threshold to about 10 GeV and enhances the sensitivity of detecting neutrinos
from annihilations and decays of light dark matter. To match this experimental
development, we calculate the track event rate in DeepCore array due to
neutrino flux produced by annihilations and decays of galactic dark matter. We
also calculate the background event rate due to atmospheric neutrino flux for
evaluating the sensitivity of DeepCore array to galactic dark matter
signatures. Unlike previous approaches, which set the energy threshold for
track events at around 50 GeV (this choice avoids the necessity of including
oscillation effect in the estimation of atmospheric background event rate), we
have set the energy threshold at 10 GeV to take the full advantage of DeepCore
array. We compare our calculated sensitivity with those obtained by setting the
threshold energy at 50 GeV. We conclude that our proposed threshold energy
significantly improves the sensitivity of DeepCore array to the dark matter
signature for GeV in the annihilation scenario and
GeV in the decay scenario.Comment: 19 pages, 5 figures; match the published versio
Quark-gluon vertex with an off-shell O(a)-improved chiral fermion action
We perform a study the quark-gluon vertex function with a quenched Wilson
gauge action and a variety of fermion actions. These include the domain wall
fermion action (with exponentially accurate chiral symmetry) and the Wilson
clover action both with the non-perturbatively improved clover coefficient as
well as with a number of different values for this coefficient. We find that
the domain wall vertex function behaves very well in the large momentum
transfer region. The off-shell vertex function for the on-shell improved clover
class of actions does not behave as well as the domain wall case and,
surprisingly, shows only a weak dependence on the clover coefficient
for all components of its Dirac decomposition and across all momenta. Including
off-shell improvement rotations for the clover fields can make this action
yield results consistent with those from the domain wall approach, as well as
helping to determine the off-shell improved coefficient .Comment: 11 pages, 13 figures, REVTeX
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