arXiv 2102.020152021-02hep-ph

$B\to D\ellν_\ell$跃迁形状因子的自洽光前夸克模型分析

Self-consistent light-front quark model analysis of $B\to D\ellν_\ell$ transition form factors

Ho-Meoyng Choi

备注：: 10 pages, 3 figures, minor corrections in Sec. IV, version to appear in Phys. Rev. D
发表信息：: Phys. Rev. D 103, 073004 (2021)
DOI：: 10.1103/PhysRevD.103.073004

摘要：

在基于LF量子化的标准光阵面夸克模型（LFQM）中，研究了排他性半轻子$B\to D\ellν_\ell$-$(\ell=e, μ,τ)$衰变的跃迁形状因子$f_+(q^2)$和$f_-(q^2)$ [或$f_0(q^2)$ ].通常认为，虽然$f_+(q^2)$可以在不涉及任何危险贡献（如零模和瞬时贡献）的情况下获得，但$f_-(q^2)$接收这些危险贡献，因为它涉及电流的至少两个分量，例如$(J^+, J^-)$或$(J^+, {\bf J}_\perp)$。与通常的看法相反，我们在Drell-Yan（$q^+=0$）框架中证明了从$(J^+, J^-)$得到的$f_-(q^2)$与从$(J^+, {\bf J}_\perp)$得到的$f_-(q^2)$具有相同的结果，而不涉及标准LFQM中的这种危险贡献。在我们的数值计算中，我们得到了$B\to D\ellν_\ell$ $(\ell=e, μ,τ)$的形状因子和分支比，并与实验数据以及其他理论模型预测进行了比较。我们对${\rm Br}(B\to D\ellν_\ell)$的计算结果表明，除了非声子$B^0\to D^-τν_τ$衰变外，与实验数据基本一致。比率${\cal R}(D)=\frac{{\rm Br}(B\to Dτν_τ)}{{\rm Br}(B\to D\ell'ν_{\ell'})}$ $(\ell'=e,μ)$也被估计并且与实验数据以及其它理论预测比较。

英文摘要：

We investigate the transition form factors $f_+(q^2)$ and $f_-(q^2)$ [or $f_0(q^2)$] for the exclusive semileptonic $B\to D\ellν_\ell$ $(\ell=e, μ,τ)$ decays in the standard light-front quark model (LFQM) based on the LF quantization. The common belief is that while $f_+(q^2)$ can be obtained without involving any treacherous contributions such as the zero mode and the instantaneous contribution, $f_-(q^2)$ receives those treacherous contributions since it involves at least two components of the current, e.g. $(J^+, J^-)$ or $(J^+, {\bf J}_\perp)$. Contrary to the common belief, we show in the Drell-Yan ($q^+=0$) frame that $f_-(q^2)$ obtained from $(J^+, J^-)$ gives identical result to $f_-(q^2)$ obtained from $(J^+, {\bf J}_\perp)$ without involving such treacherous contributions in the standard LFQM. In our numerical calculations, we obtain the form factors and branching ratios for $B\to D\ellν_\ell$ $(\ell=e, μ,τ)$ and compare with the experimental data as well as other theoretical model predictions. Our results for ${\rm Br}(B\to D\ellν_\ell)$ show reasonable agreement with the experimental data except for the semitauonic $B^0\to D^-τν_τ$ decay. The ratio ${\cal R}(D)=\frac{{\rm Br}(B\to Dτν_τ)}{{\rm Br}(B\to D\ell'ν_{\ell'})}$ $(\ell'=e,μ)$ is also estimated and compared with the experimental data as well as other theoretical predictions.

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。

摘要：

英文摘要：

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