共查询到20条相似文献,搜索用时 360 毫秒
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基于北京谱仪收集的4.03GeV质心系能量下e+e-对撞数据,分析τ±τ±→e±+π±+nπ0+ν's(n=0,1,2)事例,给出分支比值Br(τ±→π±ντ)=(11.64±0.49+0.76-0.73%,Br(τ±→π±π0ντ)=(24.00±1.34+1.36-1.30%,Br(τ±→π±2π0ντ)=(9.39±1.68+1.69-1.66%. 相似文献
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本文给出了e+e-→J/ψ→V+X,V→P1P2和e+e-→J/ψ→V+X,X→P4P5过程的角分布螺旋度形式.为e+e-实验数据分析提供了理论公式. 相似文献
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在高能e+e-碰撞实验(LC)中,研究了顶色辅助的人工色(TC2)理论所预言的中性top介子 的产生. 结果表明,在LC实验中通过过程e+e-→tc, e+e-→γtc和e+e-→Ztc可以探测到πt0的物理迹象. 相似文献
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在强耦合QED相的非拓扑孤子模型中,讨论了电子动力学质量的生成机制,得到了产生正、负电子对凝聚的临界耦合常数gcrit和临界核电荷数Zcrit,定性地解释了反常e+e-峰的性质.结果表明,正、负电子对凝聚在QED强耦合相中起着重要作用. 相似文献
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A. Accioly S. Ragusa H. Blas H. Mukai 《International Journal of Theoretical Physics》2002,41(6):1019-1025
Massive particles of spin 0 and 1 violate the equivalence principle (EP) at the tree level. On the other hand, if these particles are massless, they agree with the EP, which leads us to conjecture that from a semiclassical viewpoint massless particles, no matter what their spin, obey the EP. General relativity predicts a deflection angle of 2.63 for a nonrelativistic spinless massive boson passing close to the Sun, while for a massive vectorial boson of spin 1 the corresponding deflection is 2.62. 相似文献
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We study an upper bound on masses of additional scalar bosons from the electroweak precision data and theoretical constraints such as perturbative unitarity and vacuum stability in the two-Higgs-doublet model taking account of recent Higgs boson search results. If the mass of the Standard-Model-like Higgs boson is rather heavy and is outside the allowed region by the electroweak precision data, such a discrepancy should be compensated by contributions from the additional scalar bosons. We show the upper bound on masses of the additional scalar bosons to be about 2 (1) TeV for the mass of the Standard-Model-like Higgs boson to be 240 (500) GeV. 相似文献
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P. Van Isacker 《Frontiers of Physics》2018,13(6):132107
This contribution reviews the symmetry properties of the interacting boson model of Arima and Iachello. While the concept of a dynamical symmetry is by now a familiar one, this is not necessarily so for the extended notions of partial dynamical symmetry and quasi dynamical symmetry, which can be beautifully illustrated in the context of the interacting boson model. The main conclusion of the analysis is that dynamical symmetries are scarce while their partial and quasi extensions are ubiquitous. 相似文献
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In the framework of topcolor-assisted technicolor model we calculate the contributions from the preudo Goldstone bosons and new gauge bosons to e^ e^-→ttk.We find that for reasonable ranges of the parameters,the preudo Goldstone bosons afford dominate contribution,the correction arising from new gauge bosons is negligibly small,the maximum of the relative corrections is-10% with the center-of-mass energy √s=500GeV;whereas in the case of √s=1500 GeV,the relative corrections could be up to 16%.Thus large new physics might be observable at the experiments of next-generation linear colliders. 相似文献
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We study bounds and signatures of models where the Higgs doublet has an inhomogeneous mass or vacuum expectation value, being coupled to a hidden sector that breaks Lorentz invariance. This physics is best described by a low-energy effective Lagrangian in which the Higgs speed-of-light is smaller than c; such effect is naturally small because it is suppressed by four powers of the inhomogeneity scale. The Lorentz violation in the Higgs sector is communicated at tree level to fermions (via Yukawa interactions) and to massive gauge bosons, although the most important effect comes from one-loop diagrams for photons and from two-loop diagrams for fermions. We calculate these effects by deriving the renormalization-group equations for the speed-of-light of the Standard Model particles. An interesting feature is that the strong coupling dynamically makes the speed-of-light equal for all colored particles. 相似文献
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The spectra and E2 transition properties of 146-156Nd isotopes are studied in the interacting boson model in the light of new experimental data. It is found that 146-150Nd are in the transition from the vibrational limit to the rotational limit. From 152Nd onward, the isotopes are nearly perfect rotors. Possible deformation saturation is discussed in the interacting boson model. 相似文献
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A.C.A. Oliveira R. Rosenfeld 《Physics letters. [Part B]》2011,702(4):201-204
In this Letter we study a novel effect of a hidden sector coupling to the standard model Higgs boson: an enhancement of the Higgs pair production cross section near threshold due to bound state effects. After summing the ladder contributions of the hidden sector to the effective ggHH coupling, we find the amplitude for gluon-gluon scattering via a Higgs loop. We relate this amplitude to the double Higgs production cross section via the optical theorem. We find that enhancements of the O(100) for the partonic cross section near the threshold region can be obtained for a hidden sector strongly coupled to the Higgs boson. The corresponding cross section at the LHC can be as large as O(10) times the SM result for extreme values of the coupling. The detection of such an effect could in principle lead to important information about the hidden sector. 相似文献
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In this work, we analyze the positive parity of states of odd-A Eu isotopes within the framework of interacting boson fermion model (IBFM-1). The result of an IBFM-1 multilevel calculation with the 3s1/2, 2d3/2, 2d5/2, and 1g7/2 single panicle orbits is reported for the positive parity states of the odd-A Eu isotopes. A/so, an IBM-1 calculation is presented for the low-lying states in the even-even 152-154Sm core nucleus. The energy levels and B(E2) transition probabilities are calculated and compared with the experimental data. It is found that the calculated positive parity low spin state energy spectra of the odd-A Eu isotopes agree quite well with the experimental data. 相似文献
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In this paper we investigate the effects of the large extra dimensions on the two processes
e+e-→
H0Z0Z0 and e+e-→ H0Z0Z0 at linear colliders in both unpolarized and polarized collision modes. We
find that the virtual Kaluza-Klein graviton exchange can significantly enhance the cross section from their standard model expectations for these two processes. The results show that the
LED effect on the process
e+e-→
H0Z0Z0
allows the observation limits on
the effective scale MS to be probed up to 9.75 TeV and 10.1 TeV
in the unpolarized and
+-(λe+=1/2,
λe-=-1/2) polarized beam collision modes (with
Pe+=0.6,
Pe-=0.8), respectively. For the process
e+e-→
H0Z0Z0, these limits on MS can be
probed up to 6.06 TeV and 6.38 TeV in the unpolarized and polarized
collision modes separately. We find that the λe+=1/2,
λe-=-1/2 polarization collision mode in both
process e+e-→ H0Z0Z0 and e+e-→ H0Z0Z0
may provide a possibility to improve the
sensitivity in probing the LED effects. 相似文献