论文标题
$ b^ - \ to \ ell^ - \barν_\ ell \ ell \ ell^{\ prime-} \ ell^{\ prime+} $ formals offors $ b^ - \ to \ ell^ - \ ell^ -
Dispersion relations for $B^- \to \ell^- \barν_\ell \ell^{\prime-} \ell^{\prime+}$ form factors
论文作者
论文摘要
使用分散方法，我们研究$ b \toγ^*$ formaus的表征$ b^ - \ to \ ell^ - \barν_\ ell \ ell \ ell \ ell \ ell \ ell^{\ prime-} \ ell^ell^{\ ell^{\ prime+} $。我们讨论了由完整的$ b^ - \ to \ ell^ - \barν_\ ell \ ell^{\ prime-} \ ell^{\ prime+} $振幅的分离引起的歧义，这是在hadronic张量和最终状态 - 辐射片中的效果，包括来自非vanishing lepton lepton群体的影响。为了获得分散处理的资格，我们提出了辐射部分的分解，该部分导致四个不含运动学奇异性的形式。通过建立一组分散关系，我们将$ b \与γ^*$形式相关的形式与众所周知的$ b \ to v $，$ v =ω（782），ρ（770）$，类似物。利用在保形变量中的串联扩展和矢量 - 含量占主导地位的组合来参数化$ b \toγ^*$ form actos，我们从$ b \ to b \ to v $的可用输入中推断出相关未知参数的值。我们形式主义的现象学应用包括确定该过程的分支比率和前后不对称的不对称，\ el^ - \ ell^ - \barν_\ ell \ ell \ ell \ ell \ ell \ ell^{\ prime-} \ ell^\ ell^\ ell^{\ ell^{\ prime+prime+} $对于这两个最轻的Leptons for twemest最轻。
Using dispersive methods, we study the $B \to γ^*$ form factors underlying the decay $B^- \to \ell^- \barν_\ell \ell^{\prime-} \ell^{\prime+}$. We discuss the ambiguity that arises from a separation of the full $B^- \to \ell^- \barν_\ell \ell^{\prime-} \ell^{\prime+}$ amplitude into a hadronic tensor and a final-state-radiation piece, including effects from nonvanishing lepton masses. For the eligibility of a dispersive treatment, we propose a decomposition of the hadronic part that leads to four form factors that are free of kinematic singularities. By establishing a set of dispersion relations, we then relate the $B \to γ^*$ form factors to the well-known $B \to V$, $V=ω(782),ρ(770)$, analogues. Using the combination of a series expansion in a conformal variable and a vector-meson-dominance ansatz to parameterize the $B \to γ^*$ form factors, we infer the values of the associated unknown parameters from the available input on $B \to V$. The phenomenological application of our formalism includes the determination of the branching ratios and forward-backward asymmetries of the process $B^- \to \ell^- \barν_\ell \ell^{\prime-} \ell^{\prime+}$ for the two lightest leptons.
