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arXiv 0704.0601hep-phhep-ex
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具有非么正矩阵的最小Higgs模型中的D- \bar D混合和稀有D衰变

D-\bar D mixing and rare D decays in the Littlest Higgs model with non-unitarity matrix

Chuan-Hung Chen, Chao-Qiang Geng, Tzu-Chiang Yuan

摘要:

我们研究了最小Higgs模型中的$D-\bar D$混合和稀有D衰变。通过引入电荷为2/3的新的弱单重夸克来抵消顶夸克引起的二次发散,将标准么正$3\times 3$ Cabibbo-Kobayashi-Maskawa矩阵推广为夸克带电流中的非么正$4\times 3$矩阵,在树水平上产生了Z介导的变味中性流.在这个模型中,我们发现$D-\bar D$混合参数可以和当前的实验值一样大,并且$D\to X_u \ga$的衰变分支比(BR)很小,但它的直接CP不对称性可能是$O(10%)$ .另外,我们还发现$D\to X_u \ell^{+} \ell^{-}$、$D\to X_uν\bar ν$和$D\to μ^{+} μ^{-}$的BR值可以分别提高到$O(10^{-9})$、$O(10^{-8})$和$O(10^{-9})$。

英文摘要:

We study the $D-\bar D$ mixing and rare D decays in the Littlest Higgs model. As the new weak singlet quark with the electric charge of 2/3 is introduced to cancel the quadratic divergence induced by the top-quark, the standard unitary $3\times 3$ Cabibbo-Kobayashi-Maskawa matrix is extended to a non-unitary $4\times 3$ matrix in the quark charged currents and Z-mediated flavor changing neutral currents are generated at tree level. In this model, we show that the $D-\bar D$ mixing parameter can be as large as the current experimental value and the decay branching ratio (BR) of $D\to X_u \ga$ is small but its direct CP asymmetry could be $O(10%)$. In addition, we find that the BRs of $D\to X_u \ell^{+} \ell^{-}$, $D\to X_uν\bar ν$ and $D\to μ^{+} μ^{-}$ could be enhanced to be $O(10^{-9})$, $O(10^{-8})$ and $O(10^{-9})$, respectively.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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