7,692 research outputs found
The K-Z Equation and the Quantum-Group Difference Equation in Quantum Self-dual Yang-Mills Theory
From the time-independent current \tcj(\bar y,\bar k) in the quantum
self-dual Yang-Mills (SDYM) theory, we construct new group-valued quantum
fields and which satisfy
a set of exchange algebras such that fields of \tcj(\bar y,\bar k)\sim\tilde
U(\bar y,\bar k)~\partial\bar y~\tilde U^{-1}(\bar y,\bar k) satisfy the
original time-independent current algebras. For the correlation functions of
the products of the and fields defined in the invariant state constructed through the current
\tcj(\bar y,\bar k) we can derive the Knizhnik-Zamolodchikov (K-Z) equations
with an additional spatial dependence on . From the and fields we construct the
quantum-group generators --- local, global, and semi-local --- and their
algebraic relations. For the correlation functions of the products of the
and fields defined in the invariant state
constructed through the semi-local quantum-group generators we obtain the
quantum-group difference equations. We give the explicit solution to the two
point function.Comment: 15 pages, uses phyzz
Analysis of Two-Body Decays of Charmed Baryons Using the Quark-Diagram Scheme
We give a general formulation of the quark-diagram scheme for the nonleptonic
weak decays of baryons. We apply it to all the decays of the antitriplet and
sextet charmed baryons and express their decay amplitudes in terms of the
quark-diagram amplitudes. We have also given parametrizations for the effects
of final-state interactions. For SU(3) violation effects, we only parametrize
those in the horizontal -loop quark diagrams whose contributions are solely
due to SU(3)-violation effects. In the absence of all these effects, there are
many relations among various decay modes. Some of the relations are valid even
in the presence of final-state interactions when each decay amplitude in the
relation contains only a single phase shift. All these relations provide useful
frameworks to compare with future experiments and to find out the effects of
final-state interactions and SU(3) symmetry violations.Comment: 28 pages, 20 Tables in landscape form, 4 figures. Main changes are:
(i) some errors in the Tables and in the relations between the quark-diagram
amplitudes of this paper and those of Ref.[10] are corrected, (ii)
improvements are made in the presentation so that comparisons with previous
works and what have been done to include SU(3) breaking and final-state
interactions are more clearly stated; to appear in the Physical Review
Direct CP violation in two-body hadronic charmed meson decays
Motivated by the recent observation of CP violation in the charm sector by
LHCb, we study direct CP asymmetries in the standard model (SM) for the singly
Cabibbo-suppressed two-body hadronic decays of charmed mesons using the
topological-diagram approach. In this approach, the magnitude and the phase of
topological weak annihilation amplitudes which arise mainly from final-state
rescattering can be extracted from the data. Consequently, direct CP asymmetry
at tree level can be reliably estimated. In general, it
lies in the range . Short-distance QCD
penguins and penguin annihilation are calculated using QCD factorization. Their
effects are generally small, especially for modes. Since weak penguin
annihilation receives long-distance contributions from the color-allowed tree
amplitude followed by final-state rescattering, it is expected to give the
dominant contribution to the direct CP violation in the decays
and in which is absent. The maximal
, the direct CP asymmetry difference between the
above-mentioned two modes, allowed in the SM is around -0.25%, more than
away from the current world average of .Comment: 19 pages, 2 figures; typos correcte
One Dimensional ary Density Classification Using Two Cellular Automaton Rules
Suppose each site on a one-dimensional chain with periodic boundary condition
may take on any one of the states , can you find out the most
frequently occurring state using cellular automaton? Here, we prove that while
the above density classification task cannot be resolved by a single cellular
automaton, this task can be performed efficiently by applying two cellular
automaton rules in succession.Comment: Revtex, 4 pages, uses amsfont
Higher-dimensional WZW Model on K\"ahler Manifold and Toroidal Lie Algebra
We construct a generalization of the two-dimensional Wess-Zumino-Witten model
on a -dimensional K\"ahler manifold as a group-valued non-linear sigma
model with an anomaly term containing the K\"ahler form. The model is shown to
have an infinite-dimensional symmetry which generates an -toroidal Lie
algebra. The classical equation of motion turns out to be the
Donaldson-Uhlenbeck-Yau equation, which is a -dimensional generalization of
the self-dual Yang-Mills equation.Comment: 12 pages, Late
Dynamique culturelle et service social des groupes. Pratique clinique en milieux multiculturels
Face aux changements majeurs que connaît notre démographie, comment pouvons-nous assurer la pertinence culturelle du service social des groupes auprès des différentes populations auxquelles il s'adresse ? Le présent exposé propose une conception du service social des groupes qui tient compte du sens profond et de la nature unique de la vie dans nos milieux multiculturels. Il traite de questions relatives aux différences culturelles et à l'acculturation en termes d'impacts majeurs sur le bien-être psychologique et social des gens. L'article décrit quatre volets de la pratique du service social des groupes : le traitement et le support; l'éducation et la prévention; la défense des droits de la personne; l'accroissement du pouvoir des individus. Cette approche de l'intervention de groupe constitue une façon de repenser le service social des groupes en fonction de la croissance du multiculturalisme
Enhancing Organizational Performance by Knowledge Sharing
Knowledge management can be regarded as one of the key processes of organizational learning. It is well accepted that learning organizations can enhance their capability and hence competitiveness and performance through learning. Recognizing the importance of knowledge management, researchers are interested in exploring knowledge sharing activities because such activities are the cornerstone of other knowledge management activities. It is argued that a fundamental purpose of managing knowledge is to establish a shared context in organizations. As such, what factors affect interpersonal knowledge sharing and how they affect interpersonal knowledge sharing in organizations are critical and worth noting. A preliminary model from an organizational behavior perspective is proposed which will serve as the framework for further study
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