49,737 research outputs found
From Competition to Complementarity: Comparative Influence Diffusion and Maximization
Influence maximization is a well-studied problem that asks for a small set of
influential users from a social network, such that by targeting them as early
adopters, the expected total adoption through influence cascades over the
network is maximized. However, almost all prior work focuses on cascades of a
single propagating entity or purely-competitive entities. In this work, we
propose the Comparative Independent Cascade (Com-IC) model that covers the full
spectrum of entity interactions from competition to complementarity. In Com-IC,
users' adoption decisions depend not only on edge-level information
propagation, but also on a node-level automaton whose behavior is governed by a
set of model parameters, enabling our model to capture not only competition,
but also complementarity, to any possible degree. We study two natural
optimization problems, Self Influence Maximization and Complementary Influence
Maximization, in a novel setting with complementary entities. Both problems are
NP-hard, and we devise efficient and effective approximation algorithms via
non-trivial techniques based on reverse-reachable sets and a novel "sandwich
approximation". The applicability of both techniques extends beyond our model
and problems. Our experiments show that the proposed algorithms consistently
outperform intuitive baselines in four real-world social networks, often by a
significant margin. In addition, we learn model parameters from real user
action logs.Comment: An abridged of this work is to appear in the Proceedings of VLDB
Endowment (PVDLB), Vol 9, No 2. Also, the paper will be presented in the VLDB
2016 conference in New Delhi, India. This update contains new theoretical and
experimental results, and the paper is now in single-column format (44 pages
Evaluating decay Rates and Asymmetries of into Light Baryons in LFQM
In this work we calculate the branching ratios of semi-leptonic and
non-leptonic decays of into light baryons ( and ), as
well as the measurable asymmetries which appear in the processes, in the light
front quark model (LFQM). In the calculation, we adopt the diquark picture and
discuss the justifiability of applying the picture in our case. Our result on
the branching ratio of is in good agreement with
data. More predictions are made in the same model and the results will be
tested in the future experiments which will be conducted at LHCb and even ILC.Comment: 20 page, 8 talbes, 1 figure; Some changes were made. Accepted by PR
Interaction of cosmic background neutrinos with matter of periodic structure
We study coherent interaction of cosmic background neutrinos(CBNs) with
matter of periodic structure. The mixing and small masses of neutrinos
discovered in neutrino oscillation experiments indicate that CBNs which have
very low energy today should be in mass states and can transform from one mass
state to another in interaction with electrons in matter. We show that in a
coherent scattering process a periodic matter structure designed to match the
scale of the mass square difference of neutrinos can enhance the conversion of
CBNs from one mass state to another. Energy of CBNs can be released in this
scattering process and momentum transfer from CBNs to electrons in target
matter can be obtained.Comment: 6 pages, 5 figures, publication versio
B meson decays to baryons in the diquark model
We study B meson decays to two charmless baryons in the diquark model,
including strong and electroweak penguins as well as the tree operators. It is
shown that penguin operators can enhance \bar{B} \to \Bb_s \bar{\Bb}
considerably, but affect \bar{B} \to \Bb_1 \bar{\Bb}_2 only slightly, where
\Bb_{(1,2)} and \Bb_s are non-strange and strange baryons, respectively.
The dependence of the decay rates due to tree-penguin interference is
illustrated. In principle, some of the \Bb_s \bar{\Bb} modes could dominate
over \Bb_1 \bar{\Bb}_2 for , but in general the effect is
milder than their mesonic counterparts. This is because the operator can
only produce vector but not scalar diquarks, while the opposite is true for
and . Predictions from diquark model are compared to those from the
sum rule calculation. The decays \bar{B} \to \Bb_s \bar{\Bb}_s and inclusive
baryonic decays are also discussed.Comment: 9 pages, 6 figures, Revte
Covariant Light-Front Approach for transition form factors
In the covariant light-front quark model, we investigate the form factors of
decays into
mesons. The form factors in the spacelike region are directly
evaluated. To extrapolate the form factors to the full kinematic region, we fit
the form factors by adopting a three-parameter form from the spacelike region.
transition form factors at maximally recoiling point () are
smaller than and transition form factors, while the form factors at zero recoiling point are close to each other. In the
fitting procedure, we find the parameters for the form factors and strongly depend on the decay constants of
and mesons. Fortunately, the semileptonic and nonleptonic decays
are not sensitive to these form factors. With the form factors, we also
investigate the branching fractions, polarizations of the semileptonic decays. Semileptonic and decays have much larger branching fractions than . In the three kinds of decays, contributions
from the longitudinal polarized vector is comparable with those from the
transversely polarized vector. These predictions will be tested at the ongoing
and forthcoming hadron colliders.Comment: 15 pages, 1 figure, uncertainties reanalyzed, several parts
reorganized, conclusions unchange
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