7,948 research outputs found

    Resolving the Degeneracy in Single Higgs Production with Higgs Pair Production

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    The Higgs boson production can be affected by several anomalous couplings, e.g. ctc_t and cgc_g anomalous couplings. Precise measurement of ggβ†’hgg\to h production yields two degenerate parameter spaces of ctc_t and cgc_g; one parameter space exhibits the SM limit while the other does not. Such a degeneracy could be resolved by Higgs boson pair production. In this work we adapt the strategy suggested by the ATLAS collaboration to explore the potential of distinguishing the degeneracy at the 14 TeV LHC. If the ctc_t anomalous coupling is induced only by the operator H†HQΛ‰LH~tRH^\dag H \bar Q_L \tilde{H} t_R, then the non-SM-like band could be excluded with an integrated luminosity of ∼235Β fbβˆ’1\sim 235~{\rm fb}^{-1}. Making use of the fact that the Higgs boson pair is mainly produced through an ss-wave scattering, we propose an analytical function to describe the fraction of signal events surviving a series of experimental cuts for a given invariant mass of Higgs boson pair. The function is model independent and can be applied to estimate the discovery potential of various NP models

    Simple non-Abelian extensions of the standard model gauge group and the diboson excesses at the LHC

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    The ATLAS collaboration reported excesses at around 2 TeV in the di-boson production decaying into hadronic final states. We consider the possibility of explaining the excesses with extra gauge bosons in two simple non-Abelian extensions of the Standard Model. One is the so-called G(221)G(221) models with a symmetry structure of SU(2)1βŠ—SU(2)2βŠ—U(1)XSU(2)_1\otimes SU(2)_2\otimes U(1)_X and the other is the G(331)G(331) models with an extended symmetry of SU(3)CβŠ—SU(3)LβŠ—U(1)XSU(3)_C\otimes SU(3)_L\otimes U(1)_X. The Wβ€²W' and Zβ€²Z' bosons emerge after the electroweak symmetry is spontaneously broken. Two patterns of symmetry breaking in the G(221)G(221) models are considered in this work: one is SU(2)LβŠ—SU(2)2βŠ—U(1)Xβ†’SU(2)LβŠ—U(1)YSU(2)_L\otimes SU(2)_2 \otimes U(1)_X \to SU(2)_L\otimes U(1)_Y, the other is SU(2)1βŠ—SU(2)2βŠ—U(1)Yβ†’SU(2)LβŠ—U(1)YSU(2)_1\otimes SU(2)_2 \otimes U(1)_Y \to SU(2)_L\otimes U(1)_Y. The symmetry breaking of the G(331)G(331) model is SU(3)LβŠ—U(1)Xβ†’SU(2)LβŠ—U(1)YSU(3)_L\otimes U(1)_X \to SU(2)_L \otimes U(1)_Y. We perform a global analysis of Wβ€²W^\prime and Zβ€²Z^\prime phenomenology in ten new physics models, including all the channels of Wβ€²/Zβ€²W^\prime/Z^\prime decay. Our study shows that the leptonic mode and the dijet mode of Wβ€²/Zβ€²W^\prime/Z^\prime decays impose a very stringent bound on the parameter space in several new physics models. Such tight bounds provide a useful guide for building new physics models to address on the diboson anomalies. We also note that the Left-Right and Lepton-Phobic models can explain the 3.4Οƒ3.4\sigma WZWZ excess if the 2.6Οƒ2.6\sigma deviation in the W+Wβˆ’W^+W^- pair around 2~TeV were confirmed to be a fluctuation of the SM backgrounds.Comment: Publish version; title changed as suggested by journal Edito

    FDserver: A web service for protein folding research

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    *Summary:* To facilitate the study of protein folding, we have developed a web service for protein folding rate and folding type prediction as well as for the calculation of a variety of topological parameters of protein structure, which is freely available to the community.
*Availability:* http://sdbi.sdut.edu.cn/FDserve

    Probing dark particles indirectly at the CEPC

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    When dark matter candidate and its parent particles are nearly degenerate, it would be difficult to probe them at the Large Hadron Collider directly. We propose to explore their quantum loop effects at the CEPC through the golden channel process e+eβˆ’β†’ΞΌ+ΞΌβˆ’e^+e^-\to \mu^+\mu^-. We use a renormalizable toy model consisting of a new scalar and a fermion to describe new physics beyond the Standard Model. The new scalar and fermion are general multiplets of the SU(2)LΓ—U(1)YSU(2)_L\times U(1)_Y symmetry, and couple to the muon lepton through Yukawa interaction. We calculate their loop contributions to anomalous Ξ³ΞΌ+ΞΌβˆ’\gamma\mu^+\mu^- and ZΞΌ+ΞΌβˆ’Z\mu^+\mu^- couplings which can be applied to many new physics models. The prospects of their effects at the CEPC are also examined assuming a 0.002 accuracy in the cross section measurement

    Research on the MPA Education and Training Model with Internal Structure; Teaching Perspective as the Core and Double Loop; as the Main Body

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    Over the past two decades China s MPA education has undergone a transformation from high-speed development to high-quality development However there are still problems and challenges in the current development of MPA education in China In the new era MPA education should take the opportunity of comprehensive improvement and innovation of education to reform its teaching and innovate its training methods Change the traditional external transmission teaching perspective and build a internal structure teaching perspective with a dynamic knowledge perspective a proactive student perspective and an active learning perspective as the core Give full play to the joint efforts of schools government and society and form a double loop talent training model that integrates theoretical knowledge and management practice Promote MPA students to achieve research-based learning cooperative learning social learning and innovative learning enhance the quality of talent cultivation and help to achieve a new realm of Chinese governanc
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