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arXiv 1310.2889hep-phhep-ex
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阈附近S波重介子对产额的同位旋破坏

Isospin violation in the yield of S-wave heavy meson pairs near threshold

Xin Li, M. B. Voloshin

摘要:

我们考虑了由重$D^{(*)}$或$B^{(*)}$介子和反介子组成的中性对的产生过程,其中中性对可以在$S$波中产生,如$e^+e^- \to π^0 \, D^* \bar D^{(*)}$和$e^+e^- \to γ\, D^{(*)} \bar D^{(*)}$,以及与$B^{(*)}$介子的类似反应。在重介子对的阈值附近,带电介子对与中性介子对的产额之比$R^{c/n}$受同位素质量差和带电介子间库仑相互作用引起的同位旋破缺的强烈影响。$R^{c/n}$中的同位旋破缺的实际行为对重介子之间的强相互作用也很敏感,因此实验测量这个比值可以作为这种强相互作用的探针。我们计算$R^{c/n}$在和非常接近的阈值的介子对的同位素散射长度。特别是,我们发现,对带电介子的产率不去零,正是在阈值,而是从一个有限的步骤,其高度取决于在一个特定的通道中的散射长度的值。

英文摘要:

We consider production of overall neutral pairs consisting of heavy $D^{(*)}$ or $B^{(*)}$ meson and antimeson in the processes, where the pair can be created in an $S$-wave, such as $e^+e^- \to π^0 \, D^* \bar D^{(*)}$ and $e^+e^- \to γ\, D^{(*)} \bar D^{(*)}$, and similar reactions with $B^{(*)}$ mesons. The ratio $R^{c/n}$ of the yield of pairs of charged mesons to that of neutral mesons near the threshold for the heavy pair is strongly affected by the isospin breaking due to the isotopic mass differences and due to the Coulomb interaction between the charged mesons. The actual behavior of the isospin breaking in $R^{c/n}$ is also sensitive to the strong interaction between the heavy mesons, so that experimental measurement of this ratio can be used as a probe of this strong interaction. We calculate $R^{c/n}$ at and very near the threshold in terms of the isotopic scattering lengths for the meson pairs. In particular we find that the yield of pairs of charged mesons does not go to zero at exactly the threshold, but rather starts with a finite step, whose height depends on the value of the scattering length in a particular channel.

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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