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New signature of low mass Z'in J/ψdecays

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Chinese Physics C 2024年第8期48卷 1-5页

作者： chao-qiang geng Chia-Wei Liu Jiabao Zhang School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China Tsung-Dao Lee Institute&School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Institute of Theoretical Physics University of Chinese Academy of SciencesBeijing 100190China

We explored a new approach to search for a low-mass Z′particle through J/ψdecays by identifying its existence through parity-violating phenomena in the isospin-violating final states ofΛΣ¯^(0)and the corresponding charge conjugated states ofΛΣ¯^(0).Our investigation centered on a generation-independent and leptophobic Z′with mass below 10 *** the present experimental conditions at Beijing Spectrometer III(BESIII)and the anticipated opportunities at the Super Tau Charm Factory(STCF),we conducted Monte-Carlo simulations to predict possible events at both ***,we foresee a substantial enhancement in the precision of the lower limit estimation ofαNP as well as a reduction in statistical uncertainty with upcoming STCF ***,it is essential to highlight that a null result in the measurement ofαNP would impose stringent constraints,requiring the Z′−q−q couplings to be in the order of 10^(−2).

关键词： Z′ parity violation J/ψ

Observational constraints on running vacuum model

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Chinese Physics C 2019年第2期43卷 132-137页

作者： Jin-Jun Zhang Chung-Chi Lee chao-qiang geng School of Physics and Information Engineering Shanxi Normal University DAMTP Centre for Mathematical Sciences University of Cambridge Department of Physics National Tsing Hua University National Center for Theoretical Sciences

We investigate the power spectra of the CMB temperature and matter density in the running vacuum model(RVM) with the time-dependent cosmological constant of A=3 vH^2+ Λ_0, where H is the Hubble parameter. In this model, dark energy decreases in time and decays to both matter and radiation. By using the Markov chain Monte Carlo method, we constrain the model parameter v as well as the cosmological observables. Explicitly, we obtain v ≤1.54× 10^(-4)(68% confidence level) in the RVM with the best-fit χ_(RVM)~2 =13968.8, which is slightly smaller thanχ_(ΛCDM)~2= 13969.8 in the ΛCDM model of v = 0.

关键词： matter power spectrum running vacuum model CMB temperature spectrum cosmological constant

Running vacuum model in a non-flat universe

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Chinese Physics C 2020年第10期44卷 178-184页

作者： chao-qiang geng Yan-Ting Hsu Lu Yin Kaituo Zhang School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study UCASHangzhou 310024 International Centre for Theoretical Physics Asia-Pacific Beijing/Hangzhou Department of Physics National Tsing Hua UniversityHsinchu300 National Center for Theoretical Sciences Hsinchu300 Department of Physics Anhui Normal UniversityWuhuAnhui 241000 Collaborative Innovation Center of Light Manipulations and Applications Shandong Normal UniversityJinan 250358

We investigate observational constraints on the running vacuum model(RVM)ofΛ=3v(H^2+K/a^2)+c0 in a spatially curved universe,where is the model parameter,K corresponds to the spatial curvature constant,represents the scalar factor,and co is a constant defined by the boundary *** study the CMB power spectra with several sets of and K in the *** fitting the cosmological data,we find that the best fitted x^2 value for RVM is slightly smaller than that of CDM in the non-flat universe,along with the constraints of v≤O(10^-4)(68%C.L.)and|ΩK=-K/(aH)^2|≤O(10^-2)(95%C.L.).In particular,our results favor the open universe in both CDM and *** addition,we show that the cosmological constraints of∑mv=0.256^+0.224-0.234(RVM)and∑mv=0.257^+0.219-0.234(ΛCDM)at 95%*** the neutrino mass sum are relaxed in both models in the spatially curved universe.

关键词： cosmological parameters from CMBR cosmological simulations dark energy theory

Center of mass motion in bag model

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Chinese Physics C 2023年第1期47卷 168-179页

作者：刘佳韦耿朝强 School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China University of ChineseAcademy of Sciences Beijing 100190China

Despite its success with mass spectra,the reputation of the bag model has been marred by embarrassment of the center of mass *** leads to severe theoretical *** instance,the masses and the decay constants would no longer be independent of the *** this work,we provide a systematic approach to resolving this *** framework can consistently compute the meson decay constants and baryon transition form ***,the form factors in the neutronβdecays do not depend on any free parameters and are determined to be F1V=1and F1A=1.31or F1A/F1V=1.31,which is close to the experimental value of F1A/F1V=*** addition,we find that B(Λb→Λγ)=(6.8±3.3)×10-6,which agrees to the experimental value of(7.1±1.7)×10-6.

关键词： form factors quark model week interactions

W-boson mass anomaly from a general SU(2)_(L)scalar multiplet

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Chinese Physics C 2023年第6期47卷 15-35页

作者：吴佳骏黄达耿朝强 School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China University of Chinese Academy of Sciences(UCAS) Beijing 100049China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China International Centre for Theoretical Physics Asia-Pacific Beijing/HangzhouChina National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China

We explain the W-boson mass anomaly by introducing an SU(2)_(L)scalar multiplet with general isospin and hypercharge{in the case without its vacuum expectation value}.It is shown that the dominant contribution from the scalar multiplet to the W-boson mass arises at the one-loop level,which can be expressed in terms of the electroweak(EW)oblique parameters T and S at leading *** first rederive the general formulae of T and S induced by a scalar multiplet of EW charges,confirming the results in *** then study several specific examples of great phenomenological interest by applying these general *** a result,it is found that the model with a scalar multiplet in an SU(2)_(L)real representation with Y=0 cannot generate the required M_(W)correction because it leads to vanishing values of T and ***,the cases with scalars in a complex representation under SU(2)_(L)with a general hypercharge can explain the M_(W)excess observed by CDF-Ⅱowing to nonzero T and *** further consider the strong constraints from the perturbativity and EW global fit of the precision data and vary the isospin representation and hypercharge of the additional scalar multiplet to assess the extent of the model to solve the W-boson mass *** turns out that these constraints play important roles in setting limits on the model parameter *** also briefly describe the collider signatures of the extra scalar multiplet,especially when it contains long-lived,heavy,highly charged states.

关键词： electroweak precision physics multi-Higgs models specific BSM phenomenology

Time-reversal asymmetries in Λ_(b)→Λ(→pπ^(−))ℓ^(+)ℓ^(−)

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Chinese Physics C 2024年第3期48卷 1-14页

作者：耿朝强刘佳韦魏正乙 School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China University of Chinese Academy of Sciences Beijing 100190China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China

We study the decays ofΛb→Λ(→pπ^(−))ℓ^(+)ℓ^(−)withℓ=(e,μ,τ).We examine the full angular distributions with polarizedΛb,where the T-odd observables are *** discuss the possible effects of new physics(NP)and find that the T-odd observables are sensitive to them as they vanish in the standard *** attention is given to the interference of(pseudo)scalar operators with(axial)vector operators in polarized Λ_(b)→Λ(→pπ^(−))τ^(+)τ^(−),which are studied for the first *** effects are proportional to the lepton masses and therefore may evade the constraint from Λ_(b)→Λ(→pπ^(−))μ^(+)μ^(−) at the LHCb ***Λ_(b)→Λ(→pπ^(−))τ^(+)τ^(−) is uncontaminated by the charmonia resonance,it provides a clean background to probe *** addition,we show that the experimental central value of K10 in Λ_(b)→Λ(→pπ^(−))μ^(+)μ^(−) at the LHCb can be explained by the NP case,which couples to the right-handed quarks and *** polarization fraction of Λ_(b) at the LHCb is found to be consistent with zero regardless of the NP scenarios.

关键词： time reversal asymmetry angular distribution new physics T-odd correlation

Effects and mechanisms of fluorite on the co-reduction of blast furnace dust and seaside titanomagnetite

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International Journal of Minerals,Metallurgy and Materials 2017年第11期24卷 1201-1210页

作者： Tian-yang Hu Ti-chang Sun Jue Kou chao geng Yong-qiang Zhao School of Civil and Resources Engineering University of Science and Technology Beijing Beijing 100083 China Key Laboratory of Ministry of Education of China for Efficient Mining and Safety of Metal Mines Beijing 100083 China

The co-reduction roasting and grinding-magnetic separation of seaside titanomagnetite and blast furnace dust was investigated with and without fluorite addition at a reduction roasting temperature of 1250°C for 60 min, a grinding fineness of-43 μm accounting for 69.02 wt% of the total, and a low-intensity magnetic field strength of 151 kA/m. The mineral composition, microstructure, and state of the roasted products were analyzed, and the concentrations of CO and CO_2 were analyzed in the co-reduction roasting. Better results were achieved with a small fluorite dosage(≤4 wt%) in the process of co-reduction. In addition, F^- was found to reduce the melting point and viscosity of the slag phase because of the high content of aluminate and silicate minerals in the blast furnace dust. The low moisture content of the blast furnace dust and calcic minerals inhibited the hydrolysis of CaF_2 and the loss of F^-. Compared with the blast furnace dust from Chengdeng, the blast furnace dusts from Jiugang and Jinxin inhibited the diffusion of F-when used as reducing agents, leading to weaker effects of fluorite.

关键词： seaside titanomagnetite blast furnace dust co-reduction roasting fluorite mechanisms

Emulsion Binders with Multiple Crosslinked Structures for High-Performance Lithium-Sulfur Batteries

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Chinese Journal of Polymer Science 2023年第7期41卷 1027-1036页

作者： Ya-Fang Tan Wen-qiang Wang Ling Gao Ai-Guo Guan geng-chao Wang Shanghai Key Laboratory of Advanced Polymeric Materials Shanghai Engineering Research Center of Hierarchical NanomaterialsSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghai200237China

Lithium-sulfur batteries suffer a lot from the huge volume change and the shuttle effect. However, conventional poly(vinylidene fluoride) binder has intrinsic drawbacks, such as low ion conductivity, weak polysulfide-trapping ability, poor mechanical properties, and requirement of organic solvents. Herein, we designed a functional emulsion binder with multi crosslinked structure. Such a structure was formed by the covalent crosslinking within and between the emulsion particles, which facilitates the adapting of the volume expansion of sulfur cathode, thereby ensuring the integrity of electrodes. Besides, the polar functional groups endow the binder with strong chemisorption of lithium polysulfide and fast lithium-ion migration ability. Thus, the assembled lithium-sulfur battery displayed a high initial discharge capacity of 1246 mAh·g^(−1) at 0.1 C, and a capacity fading rate of 0.04% per cycle after 500 cycles at 0.5 C. Even at a high sulfur mass loading of 4.8 mg·cm^(−2), a high capacity of 956 mAh·g^(−1) was still obtained at 0.2 C.

关键词： Acrylate copolymer Internal and external crosslinking Emulsion binders Lithium-sulfur batteries

Dominated Splitting Versus Small Angles

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Acta Mathematica Sinica,English Series 2008年第7期24卷 1163-1174页

作者： chao LIANG geng LIU Applied Mathematics Department The Central University of Finance and Economics Beijing 100081 P. R. China School of Mathematical Sciences Peking University Beijing 100871 P.R. China

In this paper, we give a partial answer to the problem proposed by Lan Wen. Roughly speaking, we prove that for a fixed i, f has C^1 persistently no small angles if and only if f has a dominated splitting of index i on the C^1 i-preperiodic set P＊^1（f）. To prove this, we mainly use some important conceptions and techniques developed by Christian Bonatti. In the last section, we also give a characterization of the finest dominated splitting for linear cocvcles.

关键词： dominated splitting linear cocycle BGV-equivalence