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arXiv 1209.1348hep-phhep-ex
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用U-自旋重新研究D0-D0bar混合

Revisiting D0-D0bar mixing using U-spin

Michael Gronau, Jonathan L. Rosner

摘要:

我们证明了在标准模型中$D^0$-$\bar D^0$混合只发生在U-自旋破缺的二级。SU(3)的U-自旋子群是分析中间态对$D^0$-$\od^0$混合参数$y = ΔΓ/(2 Γ)$的抵消作用的有力工具。取消由于状态{\it内的一个单一的U-自旋三元组}被证明是有效的U-自旋断裂的第一顺序。举例说明了由(a)对带电的π介子和K介子;(b)对中性赝标成员的介子八重态;(c)带电的矢量赝标对,和(d)四个带电的K介子和π介子的状态。

英文摘要:

We prove that $D^0$-$\bar D^0$ mixing in the standard model occurs only at second order in U-spin breaking. The U-spin subgroup of SU(3) is found to be a powerful tool for analyzing the cancellation of intermediate-state contributions to the $D^0$--$\od^0$ mixing parameter $y = ΔΓ/(2 Γ)$. Cancellations due to states {\it within a single U-spin triplet} are shown to be valid to first order in U-spin breaking. Illustrations are given for triplets consisting of (a) pairs of charged pions and kaons; (b) pairs of neutral pseudoscalar members of the meson octet; (c) charged vector-pseudoscalar pairs, and (d) states of four charged kaons and pions.

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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