共查询到18条相似文献,搜索用时 62 毫秒
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计算了人工色荷电PG玻色子π 相似文献
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利用工作在北京正负电子对撞机(BEPC)上的北京谱仪(BES)收集到的33pb-1的Ψ(3770)数据,寻找D介子味道改变中性流(FCNC)和轻子数不守恒(LNV)的稀有衰变, 包括4个D0介子的衰变模式(K0e+e-,Φe+e-,ρ0e+e-和K*0e+e-)和6个D+介子的衰变模式(K-e+e+,K+e+e-,π-e+e+, π+e+e-,K*-e+e+和K*+e+e-). 没有发现信号,给出90%置信水平的上限. 其中, D+介子的两个衰变模式D+→K*-e+e+和D+→K*+e+e-的上限是首次测量. 相似文献
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在美国BNL实验室进行的一项实验可能找到了超出粒子物理标准模型的新的物理的证据.E94 9实验组探测到相当于标准模型预言两倍的稀有的K介子衰变.实验结果在BNL的学术讨论会上做了报告,并投到PhysicsReviewLetters.K介子是一种寿命只有约1 2 0亿分之一秒的不稳定的粒子,可以通过 相似文献
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在顶色辅助的人工色(TC2)理论框架下,研究了顶夸克稀有衰变t→cV过程.结果表明TC2模型预言的标量粒子top-pions和top-Higgs对顶夸克稀有衰变分支比的贡献可以使其比标准模型预言值大6—9个数量级.在大多数参数范围内,分支比的数量级为:Br(t→cg)~10-5,Br(t→cZ)~10-5,Br(t→cγ)~10-7.在合理的参数范围内,顶夸克稀有衰变t→cV过程能够被未来的对撞机实验探测到.因此,顶夸克稀有衰变过程为我们提供了一种检验TC2理论的方法. 相似文献
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In this paper we calculate the contributions to the FCNC rare decay from the charged technipion P± and P8± in the frarnervork of technicolor theory. We find that: (a) P± can provide a positive but relatively small contribution to the process; (b) the contribution is large and positive for relatively light P8± and becomes negative for mp8 ≥ 531 GeV; (c) the enhancement to the ratio BR() can be as large as a factor of 30 for mp1 = 50 GeV and mp8 = 100 GeV; (d) the lower mass bound on mp8 is mp8 > 220,190 GeV for mp1 = 50,200 GeV, respectively 相似文献
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We calculate the flavor changing t → cπ0 decay in the framework of the topcolor assisted multiscaletechnicolor model. We find that (a) the branching ratio of t → cπ0 is insensitive to mπ, mπs and mπt, while it increasesquickly as ε increases; (b) for reasonable ranges of the parameters, the maximum of the branching ratio in this modelmay reach 7 × 10-6, seven orders larger compared to the one t → cH0 calculated in the standard model. This mightprovide an opportunity to detect the rare decay of the top quark in experiments. 相似文献
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We calculate PGB (pseudo-Goldstone boson) corrections to the decays B → Xsγ and B → K*γ in the MWTCM (multiscale walking technicolor model). The presence of PGBs in the MWTCM leads to large enhancements in the rates of B → Xsγ and B → K*γ. But these results are in conflict with the recent CLEO data on the branching ratios BR (B → Xsγ) and BR(B → K*γ). If topcolor is further introduced, the calculated results in the topcolor assisted MWTCM can be suppressed and be in agreemet with the CLEO data for a certain range of parameters. We also estimate the branching ratio BR (B → Xsg) in the topcolor assisted MWTCM, and this estimate is roughly one order higher than that in the standard model. 相似文献
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Based. On the effective Hamiltonian with the generalized factorization approach, we calculate the branchingratios and CP asymmetries of B → VV decays in the Topcolor-assisted Technicolor (TC2) model. Within the consideredparameter space we find that: (a) for the penguin-dominated B → K* φ and K*0 φ decays, the new physics enhancementsto the branching ratios are around 40%; (b) the measured branching ratios of B →K* φ and K*0φ decays prefer therange of 3 Neffc 5; (c) the SM and TC2 model predictions for the branching ratio B(B →ρ ρ0) are only about halfof the Belle‘s measurement; and (d) for most B → VV decays, the new physics corrections on their CP asymmetries are generally small or moderate in magnitude and insensitive to the variation of mπ and Neffc. 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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系统研究了最小Higgs(LH)模型预言的所有新粒子对Z→bb过程分支比Rb的量子修正. 结果表明此修正主要来源于类矢量夸克T、规范玻色子ZH和BH, 其数值对自由参数f, c'和xL非常敏感.Rb的最新测量数据对这些参数有很强的限制. 相似文献