论文标题
$ b \！\ to \ bar {d} _1（\ to \ bar {d}π^+π^ - ） \ bar {d}^{（*）}π^+π^ - \ ell^+en^+en
First observation of $B\!\to \bar{D}_1(\to\bar{D}π^+π^-)\ell^+ν_\ell$ and measurement of the $B\!\to \bar{D}^{(*)}π\ell^+ν_\ell$ and $B\!\to \bar{D}^{(*)}π^+π^-\ell^+ν_\ell$ branching fractions with hadronic tagging at Belle
论文作者
论文摘要
我们报告了$ b \ to \ bar {d}^{（*）}π\ ell^+en^+en^+el $和$ b \ to \ bar {d}^{（*）π^+ol el^+ell^ell^ell^ell^+el^+el ell $ b \ e $ b \ ell $ b \ e $ b \ e $ b \ e $ b \ e $ b \ el $ b \ el $ b \ ell $ b \ ell $ b \ ell^e $ b \ ell $ b \ el $ b \ ell $ b \ ell^ - \ bar {d}^*\ ell^+n+en $ $ $ \ ell = e，μ$。这些结果是从包含$ 772 \ times 10^6 b \ bar {b} $对的数据样本获得的，该数据在$υ（4S）$共振附近与kekb belle detector在Kekb非对称能量$ e^+e^+e^ - $ collider上收集。在此事件中，充分重建两个$ b $中的介子，我们获得\ begin {align*} \ frac {b（b^0 \ to \ bar {d}^0π^ - \ ell^+ell^+en^+n^+t _ \ ell）} {b（b^0 （7.24 \ pm0.36 \ pm0.12）\％\，\\ \ \ \ \ \ frac {b（b^+\ to d^-π^+\ ell^+\ ell^+g+n+en \ ell）} {b（b^+\ to \ bar bar {d} （6.78 \ pm0.24 \ pm0.15）\％\，\\ \ \ \ \ \ \ frac {b（b^0 \ to \ bar {d}^{*0}^{*0}π^ - \ ell^+ell^+n^+n+n+n+n+g \ ell）}} {b^0 \ for （11.10 \ pm0.48 \ pm0.20）\％\，\\ \ \ \ \ frac {b（b^+\ to d^{* - }π^+\ ell^+el^+n^+n+n+en \ ell）} {b（b^+\ to \ bar to \ bar { （9.50 \ pm0.33 \ pm0.27）\％\，\\ \ \ \ \ \ frac {b（b^0 \ to d^-π^+π^ - \ ell^+el^+en^+n+n \ ell）}} {b（b^0 \ to d^{ （2.91 \ pm0.37 \ pm0.25）\％\，\\ \ \ \ \\ frac {b（b^+\ to \ bar {d}^0π^0π^+π^ - \ ell^+ell^+g+t+g+t _ \ ell）}}} （3.10 \ pm0.26 \ pm0.21）\％\，\\ \ \ \\ frac {b（b^0 \ to d^{* - }π^+π^ - \ ell^+ell^+en^+n+n+n \ ell）}}} {b（b^0 （1.03 \ pm0.43 \ pm0.18）\％\，\\ \ \ \ \\ frac {b（b^+\ to \ bar {d}^{*0}π^+π^+π^ - \ ell^+ell^+ell^+ger^+ger^+end）} ＆=（1.25 \ pm0.27 \ pm0.15）\％\，\ end {align*}，其中不确定性分别是统计和系统的。研究了$dπ$，$ d^*π$和$dππ$系统的不变质谱。提取分支分数产品，其中包括$ b（b^0 \ to d_1^ - \ ell^+en^+en^+en \ ell）\ times b（d_1^ - \ to d^-π^+π^ - ）=（0.102 \ pm0.013 \ pm013 \ pm0.009） \ bar {d} _1^0 \ ell^+ν_\ ell）\ times b（\ bar {d} _1^0 \ to \ bar {d}^0π^0π^+π^ - ）=（0.105 \ pm0.011111111 \ pm0.008）\％$。
We report measurements of the ratios of branching fractions for $B \to \bar{D}^{(*)}π\ell^+ν_\ell$ and $B \to \bar{D}^{(*)}π^+π^-\ell^+ν_\ell$ relative to $B \to \bar{D}^*\ell^+ν_\ell$ decays with $\ell = e, μ$. These results are obtained from a data sample that contains $772 \times 10^6 B\bar{B}$ pairs collected near the $Υ(4S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^+e^-$ collider. Fully reconstructing both $B$ mesons in the event, we obtain \begin{align*} \frac{B(B^0 \to \bar{D}^0π^-\ell^+ν_\ell)}{B(B^0 \to D^{*-}\ell^+ν_\ell)} &= (7.24\pm0.36\pm0.12)\%\ ,\\ \frac{B(B^+ \to D^-π^+\ell^+ν_\ell)}{B(B^+ \to \bar{D}^{*0}\ell^+ν_\ell)} &= (6.78\pm0.24\pm0.15)\%\ ,\\ \frac{B(B^0 \to \bar{D}^{*0}π^-\ell^+ν_\ell)}{B(B^0 \to D^{*-}\ell^+ν_\ell)} &= (11.10\pm0.48\pm0.20)\%\ ,\\ \frac{B(B^+ \to D^{*-}π^+\ell^+ν_\ell)}{B(B^+ \to \bar{D}^{*0}\ell^+ν_\ell)} &= (9.50\pm0.33\pm0.27)\%\ ,\\ \frac{B(B^0 \to D^-π^+π^-\ell^+ν_\ell)}{B(B^0 \to D^{*-}\ell^+ν_\ell)} &= (2.91\pm0.37\pm0.25)\%\ ,\\ \frac{B(B^+ \to \bar{D}^0π^+π^-\ell^+ν_\ell)}{B(B^+ \to \bar{D}^{*0}\ell^+ν_\ell)} &= (3.10\pm0.26\pm0.21)\%\ ,\\ \frac{B(B^0 \to D^{*-}π^+π^-\ell^+ν_\ell)}{B(B^0 \to D^{*-}\ell^+ν_\ell)} &= (1.03\pm0.43\pm0.18)\%\ ,\\ \frac{B(B^+ \to \bar{D}^{*0}π^+π^-\ell^+ν_\ell)}{B(B^+ \to \bar{D}^{*0}\ell^+ν_\ell)} &= (1.25\pm0.27\pm0.15)\%\ , \end{align*} where the uncertainties are statistical and systematic, respectively. The invariant mass spectra of the $Dπ$, $D^*π$, and $Dππ$ systems are studied. Branching fraction products are extracted, among them the first observations of $B(B^0 \to D_1^-\ell^+ν_\ell) \times B(D_1^- \to D^-π^+π^-) = (0.102\pm0.013\pm0.009)\%$ and $B(B^+ \to \bar{D}_1^0\ell^+ν_\ell) \times B(\bar{D}_1^0 \to \bar{D}^0π^+π^-) = (0.105\pm0.011\pm0.008)\%$.
