5,952 research outputs found
The rare semi-leptonic decays involving orbitally excited final mesons
The rare processes , where
stands for the final meson ,
,~, ,
or~, are studied within the Standard Model. The hadronic matrix
elements are evaluated in the Bethe-Salpeter approach and furthermore a
discussion on the gauge-invariant condition of the annihilation hadronic
currents is presented. Considering the penguin, box, annihilation,
color-favored cascade and color-suppressed cascade contributions, the
observables , , and are
calculated
Two-Body Strong Decay of Z(3930) as the State
The new particle Z(3930) found by the Belle and BaBar Collaborations through
the process is identified to be the
state. Since the mass of this particle is above the threshold, the OZI-allowed two-body strong decays are the main
decay modes. In this paper, these strong decay modes are studied with two
methods. One is the instantaneous Bethe-Salpeter method within Mandelstam
formalism. The other is the combination of the model and the former
formalism. The total decay widths are 26.3 and 27.3 MeV for the methods with or
without the vertex, respectively. The ratio of over
which changes along with the mass of the initial meson
is also presented.Comment: 11 pages, 3 figure
Annihilation Rates of Heavy S-wave Quarkonia in Salpeter Method
The annihilation rates of vector charmonium and bottomonium
states and , and are estimated in the relativistic Salpeter method.
We obtained keV,
keV,
keV,
keV,
keV,
keV and
keV. In our
calculations, special attention is paid to the relativistic correction, which
is important and can not be ignored for excited , and higher excited
states.Comment: 10 pages,2 figures, 5 table
A Location-Sentiment-Aware Recommender System for Both Home-Town and Out-of-Town Users
Spatial item recommendation has become an important means to help people
discover interesting locations, especially when people pay a visit to
unfamiliar regions. Some current researches are focusing on modelling
individual and collective geographical preferences for spatial item
recommendation based on users' check-in records, but they fail to explore the
phenomenon of user interest drift across geographical regions, i.e., users
would show different interests when they travel to different regions. Besides,
they ignore the influence of public comments for subsequent users' check-in
behaviors. Specifically, it is intuitive that users would refuse to check in to
a spatial item whose historical reviews seem negative overall, even though it
might fit their interests. Therefore, it is necessary to recommend the right
item to the right user at the right location. In this paper, we propose a
latent probabilistic generative model called LSARS to mimic the decision-making
process of users' check-in activities both in home-town and out-of-town
scenarios by adapting to user interest drift and crowd sentiments, which can
learn location-aware and sentiment-aware individual interests from the contents
of spatial items and user reviews. Due to the sparsity of user activities in
out-of-town regions, LSARS is further designed to incorporate the public
preferences learned from local users' check-in behaviors. Finally, we deploy
LSARS into two practical application scenes: spatial item recommendation and
target user discovery. Extensive experiments on two large-scale location-based
social networks (LBSNs) datasets show that LSARS achieves better performance
than existing state-of-the-art methods.Comment: Accepted by KDD 201
Asymmetries and Violation in Charmed Baryon Decays into Neutral Kaons
We study the asymmetries and violations in charm-baryon
decays with neutral kaons in the final state. The asymmetry can
be used to search for two-body doubly Cabibbo-suppressed amplitudes of
charm-baryon decays, with the one in as a promising
observable. Besides, it is studied for a new -violation effect in these
processes, induced by the interference between the Cabibbo-favored and doubly
Cabibbo-suppressed amplitudes with the neutral kaon mixing. Once the new
CP-violation effect is determined by experiments, the direct asymmetry in
neutral kaon modes can then be extracted and used to search for new physics.
The numerical results based on symmetry will be tested by the
experiments in the future.Comment: 15 pages, 3 tables. Version published in JHE
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