48,948 research outputs found
Level-One Representations and Vertex Operators of Quantum Affine Superalgebra
Level-one representations of the quantum affine superalgebra
associated to the appropriate non-standard system of
simple roots and -vertex operators (intertwining operators) associated with
the level-one modules are constructed explicitly in terms of free bosonic
fields.Comment: Errors in the cocycle factors of the vertex operators and some typos
are corrected. LaTex file 17 page
Space Alignment Based on Regularized Inversion Precoding in Cognitive Transmission
For a two-tier Multiple-Input Multiple-Output (MIMO) cognitive network with common receiver, the precoding matrix has a compact relationship with the capacity performance in the unlicensed secondary system. To increase the capacity of secondary system, an improved precoder based on the idea of regularized inversion for secondary transmitter is proposed. An iterative space alignment algorithm is also presented to ensure the Quality of Service (QoS) for primary system. The simulations reveal that, on the premise of achieving QoS for primary system, our proposed algorithm can get larger capacity in secondary system at low Signal-to-Noise Ratio (SNR), which proves the effectiveness of the algorithm
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A linear mixed model approach to gene expression-tumor aneuploidy association studies.
Aneuploidy, defined as abnormal chromosome number or somatic DNA copy number, is a characteristic of many aggressive tumors and is thought to drive tumorigenesis. Gene expression-aneuploidy association studies have previously been conducted to explore cellular mechanisms associated with aneuploidy. However, in an observational setting, gene expression is influenced by many factors that can act as confounders between gene expression and aneuploidy, leading to spurious correlations between the two variables. These factors include known confounders such as sample purity or batch effect, as well as gene co-regulation which induces correlations between the expression of causal genes and non-causal genes. We use a linear mixed-effects model (LMM) to account for confounding effects of tumor purity and gene co-regulation on gene expression-aneuploidy associations. When applied to patient tumor data across diverse tumor types, we observe that the LMM both accounts for the impact of purity on aneuploidy measurements and identifies a new association between histone gene expression and aneuploidy
B_s decays at Belle
We report recent results obtained with the Belle detector using a 23.6
fb^{-1} data sample collected on the Y(5S) resonance at the KEKB asymmetric
energy e^+ e^- collider. Inclusive semileptonic B_s^0 -> X^+ l^- \nu decays are
studied for the first time and the branching fraction is measured. Combining
the electron and muon channels, we obtain Bf(B_s^0 -> X^+ l^- \nu) = (10.2 \pm
0.8 \pm 0.9)%. Also, the radiative penguin decay B_s^0 -> \phi \gamma is
observed for the first time, and an improved upper limit for the decay B_s^0
\to \gamma \gamma is obtained.Comment: Proceedings of the EPS/HEP 2007 Conference, Manchester, England, July
2007 (on behalf of the Belle collaboration), 3 pages, 2 figure
Quantum Affine Lie Algebras, Casimir Invariants and Diagonalization of the Braid Generator
Let be an infinite-dimensional quantum affine Lie
algebra. A family of central elements or Casimir invariants are constructed and
their eigenvalues computed in any integrable irreducible highest weight
representation. These eigenvalue formulae are shown to absolutely convergent
when the deformation parameter is such that . It is proven that the
universal R-matrix of satisfies the celebrated
conjugation relation with the usual twist map. As
applications, the braid generator is shown to be diagonalizable on arbitrary
tensor product modules of integrable irreducible highest weight -modules and a spectral decomposition formula for the braid generator is
obtained which is the generalization of Reshetikhin's and Gould's forms to the
present affine case. Casimir invariants acting on a specified module are also
constructed and their eigenvalues, again absolutely convergent for ,
computed by means of the spectral decomposition formula.Comment: 22 pages (many changes are made
New insights into the and other charm scalar mesons
Through the scattering of light-pseudoscalar mesons () off
charmed mesons (), we study the state and other
relevant charm scalar mesons in a unitarized chiral effective field theory
approach. We investigate the charm scalar meson poles with different
strangeness () and isospin () quantum numbers as well as their
corresponding residues, which provide the coupling strengths of the charm
scalar mesons. Both the light-quark mass and dependences of the pole
positions of the and the poles with are
analyzed in detail in this work. Interestingly we observe quite similar pion
mass trajectories for the resonance pole at around 2.1 GeV with
to those of the given in the literature. When increasing the values
of we find that a bound state and a virtual state in the
channel asymmetrically approach the threshold for , and they meet
at this threshold at . When , the bound and virtual states move
into the complex plane on the second Riemann sheet and become a symmetric pair
of resonance poles. For large enough values of , neither the
pole nor the poles with tend to fall down to
the real axis, indicating that they do not behave like a standard
quark-antiquark meson at large .Comment: 26 pages, published version in PR
The rare decay B --> X_s l^+ l^- to NNLL precision for arbitrary dilepton invariant mass
We present a new phenomenological analysis of the inclusive rare decay . In particular, we present the first calculation of the NNLL
contributions due to the leading two-loop matrix elements, evaluated for
arbitrary dilepton invariant mass. This allows to obtain the first NNLL
estimates of the dilepton mass spectrum and the lepton forward-backward
asymmetry in the high region, and to provide an
independent check of previously published results in the low region. The numerical impact of these NNLL corrections in the
high-mass region () amounts to -13% in the
integrated rate, and leads to a reduction of the scale uncertainty to .
The impact of non-perturbative contributions in this region is also discussed
in detail.Comment: 40 pages, 12 figures. v2: extended phenomenological discussion;
results unchanged; published versio
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