29,743 research outputs found
Lepton flavor violating decays induced by scalar unparticle
We study the radiative lepton flavor violating l_i -> l_j \gamma\gamma decays
in the case that the lepton flavor violation is induced by the scalar
unparticle mediation. We restrict the scaling dimension d_u and the scalar
unparticle-photon-photon coupling by using the experimental upper limit of the
branching ratio of the decay \mu -> e \gamma\gamma. Furthermore, we predict the
BRs of the other radiative decays by using the restrictions we get. We observe
that the measurements of upper limits of BRs of these decays ensure
considerable information for testing the possible signals coming from
unparticle physicsComment: 10 pages, 5 figures, 1 tabl
The XYZs of Charmonium at BES
This contribution reviews some recent developments in charmonium
spectroscopy, and discusses related theoretical predictions. The spectrum of
states, strong decays of states above open charm threshold, electromagnetic
transitions, and issues related to the recent discoveries of the "XYZ" states
are discussed. Contributions that BES can make to our understanding of
charmonium and related states are stressed in particular.Comment: 5 pages, 1 eps figure. Invited contribution to the International
Workshop on Tau-Charm Physics Charm2006 (5-7 June 2006, Beijing, China
Properties of Scalar-Quark Systems in SU(3)c Lattice QCD
We perform the first study for the bound states of colored scalar particles
("scalar quarks") in terms of mass generation with quenched SU(3)
lattice QCD. We investigate the bound states of , and
("scalar-quark hadrons"), as well as the bound states of
and quarks , i.e., , and
("chimera hadrons"). All these new-type hadrons including have a large
mass of several GeV due to large quantum corrections by gluons, even for zero
bare scalar-quark mass at . We find a similar
-dependence between and , which
indicates their similar structure due to the large mass of . From this
study, we conjecture that all colored particles generally acquire a large
effective mass due to dressed gluons
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Two novel nonlinear companding schemes with iterative receiver to reduce PAPR in multi-carrier modulation systems
Companding transform is an efficient and simple method to reduce the Peak-to-Average Power Ratio (PAPR) for Multi-Carrier Modulation (MCM) systems. But if the MCM signal is only simply operated by inverse companding transform at the receiver, the resultant spectrum may exhibit severe in-band and out-of-band radiation of the distortion components, and considerable peak regrowth by excessive channel noises etc. In order to prevent these problems from occurring, in this paper, two novel nonlinear companding schemes with a iterative receiver are proposed to reduce the PAPR. By transforming the amplitude or power of the original MCM signals into uniform distributed signals, the novel schemes can effectively reduce PAPR for different modulation formats and sub-carrier sizes. Despite moderate complexity increasing at the receiver, but it is especially suitable to be combined with iterative channel estimation. Computer simulation results show that the proposed schemes can offer good system performances without any bandwidth expansion
New neighborhood based rough sets
Neighborhood based rough sets are important generalizations of the classical rough sets of Pawlak, as neighborhood operators generalize equivalence classes. In this article, we introduce nine neighborhood based operators and we study the partial order relations between twenty-two different neighborhood operators obtained from one covering. Seven neighborhood operators result in new rough set approximation operators. We study how these operators are related to the other fifteen neighborhood based approximation operators in terms of partial order relations, as well as to seven non-neighborhood-based rough set approximation operators
Exploring Deep Space: Learning Personalized Ranking in a Semantic Space
Recommender systems leverage both content and user interactions to generate
recommendations that fit users' preferences. The recent surge of interest in
deep learning presents new opportunities for exploiting these two sources of
information. To recommend items we propose to first learn a user-independent
high-dimensional semantic space in which items are positioned according to
their substitutability, and then learn a user-specific transformation function
to transform this space into a ranking according to the user's past
preferences. An advantage of the proposed architecture is that it can be used
to effectively recommend items using either content that describes the items or
user-item ratings. We show that this approach significantly outperforms
state-of-the-art recommender systems on the MovieLens 1M dataset.Comment: 6 pages, RecSys 2016 RSDL worksho
Influence of low-level Pr substitution on the superconducting properties of YBa2Cu3O7-delta single crystals
We report on measurements on Y1-xPrxBa2Cu3O7-delta single crystals, with x
varying from 0 to 2.4%. The upper and the lower critical fields, Hc2 and Hc1,
the Ginzburg-Landau parameter and the critical current density, Jc(B), were
determined from magnetization measurements and the effective media approach
scaling method. We present the influence of Pr substitution on the pinning
force density as well as on the trapped field profiles analyzed by Hall probe
scanning.Comment: 4 pages, 5 figures, accepted for publication in J. Phys. Conf. Se
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