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arXiv 0810.0131hep-phhep-ex
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$B\to Kη,Kη^{\prime}$衰变

$B\to Kη,Kη^{\prime}$ Decays

T. N. Pham

摘要:

九态对称性方案似乎能较好地描述基态赝标介子的质量和$η-η^{\prime}$混合角,因而也可望很好地近似赝标密度算符的矩阵元,这些密度算符在末态为$η$或$η^{\prime}$的无粲二体B衰变中起重要作用.在这次演讲中,我想报告的$B^{-}\to K^{-}η, K^{-}η^{\prime}$衰变的赝标量密度算子的矩阵元素使用九态对称性的最新工作。我们发现,$B\to PP$的分支比,与一个$η$介子的最终状态符合良好的数据,而与一个$η^{\prime}$介子被低估的$20-30%$。考虑到所涉及的理论不确定性,这可以被认为是对QCDF的或多或少成功的预测。这也可能表明,额外的功率抑制项可以使分支比接近实验,因为对于$B\to K^{*}π$和$B\to K^{*}η$衰变,测量的分支比远大于QCDF预测。

英文摘要:

The nonet symmetry scheme seems to describe rather well the masses and $η-η^{\prime}$ mixing angle of the ground state pseudo-scalar mesons and is thus expected to be also a good approximation for the matrix elements of the pseudo-scalar density operators which play an important role in charmless two-body B decays with $η$ or $η^{\prime}$ in the final state. In this talk, I would like to report on a recent work on the $B^{-}\to K^{-}η, K^{-}η^{\prime}$ decay using nonet symmetry for the matrix elements of pseudo-scalar density operators. We find that the branching ratio $B\to PP$, with an $η$ meson in the final state agrees well with data, while those with an $η^{\prime}$ meson are underestimated by $20-30%$. This could be considered as a more or less successful prediction for QCDF, considering the theoretical uncertainties involved. This could also indicate that an additional power-suppressed terms could bring the branching ratio close to experiment, as with the $B\to K^{*}π$ and $B\to K^{*}η$ decay for which the measured branching ratios are much bigger than the QCDF predictions.

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