4,804 research outputs found

    Probing Electroweak Symmetry Breaking Mechanism at the LHC: A Guideline from Power Counting Analysis

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    We formulate the equivalence theorem as a theoretical criterion for sensitively probing the electroweak symmetry breaking mechanism, and develop a precise power counting method for the chiral Lagrangian formulated electroweak theories. Armed with these, we perform a systematic analysis on the sensitivities of the scattering processes W±W±→W±W±W^\pm W^\pm \rightarrow W^\pm W^\pm and qqˉ′→W±Zq\bar{q}'\rightarrow W^\pm Z for testing all possible effective bosonic operators in the chiral Lagrangian formulated electroweak theories at the CERN Large Hadron Collider (LHC). The analysis shows that these two kinds of processes are "complementary" in probing the electroweak symmetry breaking sector.Comment: Extended version, 11-page-Latex-file and 3 separate PS-Figs. To be Published in Mod.Phys.Lett.

    QCD Multipole Expansion and Hadronic Transitions in Heavy Quarkonium Systems

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    We review the developments of QCD multipole expansion and its applications to hadronic transitions and some radiative decays of heavy quarkonia. Theoretical predictions are compsred with updated experimental results.Comment: 23 pages, 7 figures. Some typos corrected, and 3 references adde

    Complex Behavior in Simple Models of Biological Coevolution

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    We explore the complex dynamical behavior of simple predator-prey models of biological coevolution that account for interspecific and intraspecific competition for resources, as well as adaptive foraging behavior. In long kinetic Monte Carlo simulations of these models we find quite robust 1/f-like noise in species diversity and population sizes, as well as power-law distributions for the lifetimes of individual species and the durations of quiet periods of relative evolutionary stasis. In one model, based on the Holling Type II functional response, adaptive foraging produces a metastable low-diversity phase and a stable high-diversity phase.Comment: 8 pages, 5 figure

    Muon anomalous magnetic moment and lepton flavor violation in MSSM

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    We give a thorough analysis of the correlation between the muon anomalous magnetic moment and the radiative lepton flavor violating (LFV) processes within the minimal supersymmetric standard model. We find that in the case when the slepton mass eigenstates are nearly degenerate, δaμ\delta a_\mu, coming from SUSY contributions, hardly depends on the lepton flavor mixing and, thus, there is no direct relation between δaμ\delta a_\mu and the LFV processes. On the contrary, if the first two generations' sleptons are much heavier than the 3rd one, i.e., in the effective SUSY scenario, the two quantities are closely related. In the latter scenario, the SUSY parameter space to account for the experimental δaμ\delta a_\mu is quite different from the case of no lepton flavor mixing. Especially, the Higgsino mass parameter μ\mu can be either positive or negative.Comment: 22 pages, 9 figures; Some discussions are modifie

    Probing Electroweak Symmetry Breaking via WW Interactions at High Energy Colliders

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    We classify the sensitivities of the future high energy hadron and electron colliders, such as the LHC and the future Linear Colliders, to probing all the next-to-leading order (NLO) bosonic operators for studying the electroweak symmetry breaking (EWSB) mechanism. We first develop a power counting rule (a generalization of Weinberg's counting method for the nonlinear sigma model) for the electroweak theories formulated by the chiral Lagrangian. Then, we formulate the Longitudinal-Goldstone Boson Equivalence Theorem as a physical criterion to discriminate the scattering processes that are not sensitive to the EWSB sector. The "complementarity" of different scattering processes via different colliders for a complete probe of all these NLO effective operators is demonstrated.Comment: Plenary talk by C.P.Y. at "Beyond the Standard Model V", Balholm, Norway, April 29 - May 4, 1997; to appear in the conference proceedings, 14 pages, Latex2
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