10,493 research outputs found
Optimal Distributed Beamforming for MISO Interference Channels
We consider the problem of quantifying the Pareto optimal boundary in the
achievable rate region over multiple-input single-output (MISO) interference
channels, where the problem boils down to solving a sequence of convex
feasibility problems after certain transformations. The feasibility problem is
solved by two new distributed optimal beamforming algorithms, where the first
one is to parallelize the computation based on the method of alternating
projections, and the second one is to localize the computation based on the
method of cyclic projections. Convergence proofs are established for both
algorithms.Comment: 7 Pages, 6 figures, extended version for the one in Proceeding of
Asilomar, CA, 201
Could be a molecular state?
We investigate whether the newly observed narrow resonance can
be described as a molecular state with quantum numbers
. Using QCD sum rules, we consider contributions up to dimension
six in the operator product expansion and work at leading order of
. The mass obtained for this state is (4.05\pm 0.28) \mbox{GeV}.
It is concluded that molecular state is a possible candidate
for .Comment: 7 pages, 4 figures.Published in Eur.Phys.J. C73 (2013) 2661. arXiv
admin note: text overlap with arXiv:1304.185
Higher order light-cone distribution amplitudes of the Lambda baryon
The improved light-cone distribution amplitudes (LCDAs) of the
baryon are examined on the basis of the QCD conformal partial wave expansion
approach. The calculations are carried out to the next-to-leading order of
conformal spin accuracy with consideration of twist 6. The next leading order
conformal expansion coefficients are related to the nonperturbative parameters
defined by the local three quark operator matrix elements with different
Lorentz structures with a covariant derivative. The nonperturbative parameters
are determined with the QCD sum rule method. The explicit expressions of the
LCDAs are provided as the main results.Comment: 17pages,10figures. arXiv admin note: text overlap with
arXiv:1311.596
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