Hadronic B decays involving even-parity charmed mesons
Hadronic B decays involving even-parity charmed mesons
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DOI：
10.1103/physrevd.68.094005
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发表时间：
2003-07
影响因子：
5
通讯作者：
Hai-Yang Cheng
中科院分区：
文献类型：
--
作者：
Hai-Yang Cheng
研究了末态含有宇称偶符的介子的强子B衰变。具体地，我们集中讨论了Cabibbo允许衰变到D^{**}\pi(\rho)，D^{**}\bar D_S^{(*)}，\bar D^{**}_sd^{(*)}$和$\bar B_S\to D_S^{**}\pi(\rho)$，其中$D^**表示一个p波符标化介子。在改进的Isgur-Scora-Grinstein-Wise夸克模型中，研究了从B到D的跃迁形式因子。我们应用重夸克有效理论和手征对称性研究了p波魅力介子的强衰变，并确定了$D_1^{1/2}-D_1^{3/2}的大小。除了衰变到$D_1(2427)^0\pi^-$外，对$B^-\to D^{**0}\pi^-$的预测与实验相符。为了避免对$D_1(2427)^0\pi^-$的严重抑制，发现$D_1^{1/2}-D_1^{3/2}$混合角的符号为正。在D_1(2427)^0\pi^-$的衰变过程中，允许颜色的树幅度和抑制颜色的树幅度之间的干扰预计是破坏性的。因此，观测比值$D_1(2427)^0\pi^-/D_1(2427)^+\pi^--可以用来检验重夸克对称性所暗示的各种形状因子的相对符号。虽然预测的$B^-与D_1(2420)^0-$在$3乘以10^-3的水平上超过了目前的上限，但它导致了从因式分解方法和比率$f_\rho/f_\pi\约1.6$所预期的比率$D_1(2420)\pi^-约2.6$。因此，对这一模型进行测量以检验因式分解假说是至关重要的。对于$\bar B\to\bar D_S^**D$衰变，期望$\bar D_{s0}^*D\gsim\bar D_{s1}D$作为重夸克极限中的衰变常数变得相同。
Hadronic B decays containing an parity-even charmed meson in the final state are studied. Specifically we focus on the Cabibbo-allowed decays $\bar B\to D^{**} \pi(\rho), D^{**}\bar D_s^{(*)}, \bar D^{**}_sD^{(*)}$ and $\bar B_s\to D_s^{**}\pi(\rho)$, where $D^{**}$ denotes generically a p-wave charmed meson. The $B\to D^{**}$ transition form factors are studied in the improved version of the Isgur-Scora-Grinstein-Wise quark model. We apply heavy quark effective theory and chiral symmetry to study the strong decays of p-wave charmed mesons and determine the magnitude of the $D_1^{1/2}-D_1^{3/2}$ mixing angle. Except the decay to $D_1(2427)^0\pi^-$ the predictions for $B^-\to D^{**0}\pi^-$ agree with experiment. The sign of $D_1^{1/2}-D_1^{3/2}$ mixing angle is found to be positive in order to avoid a severe suppression on the production of $D_1(2427)^0\pi^-$. The interference between color-allowed and color-suppressed tree amplitudes is expected to be destructive in the decay $B^-\to D_1(2427)^0\pi^-$. Hence, an observation of the ratio $D_1(2427)^0\pi^-/D_1(2427)^+\pi^-$ can be used to test the relative signs of various form factors as implied by heavy quark symmetry. Although the predicted $B^-\to D_1(2420)^0\rho^-$ at the level of $3\times 10^{-3}$ exceeds the present upper limit, it leads to the ratio $D_1(2420)\rho^-/D_1(2420)\pi^-\approx 2.6$ as expected from the factorization approach and from the ratio $f_\rho/f_\pi\approx 1.6$ . Therefore, it is crucial to have a measurement of this mode to test the factorization hypothesis. For $\bar B\to \bar D_s^{**}D$ decays, it is expected that $\bar D_{s0}^*D\gsim \bar D_{s1}D$ as the decay constants of the multiplet $(D_{s0}^*,D_{s1})$ become the same in the heavy quark limit.