从粲介子半轻子衰变到轻奇异矢量\(K^*\)介子审视轻子味普适性和跃迁形状因子相关性
Scrutinizing lepton flavor universality and transition form factor correlation from charmed meson semileptonic decay into light strange vector $K^*$ meson
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中文总结 AI 辅助
研究通过QCD光锥求和规则计算\(D_s^+ \to K^{*0}\)衰变的跃迁形状因子，构建含常规流的关联函数并利用轻锥谐振子模型，得到形状因子、分支比、CKM矩阵元值及前后不对称参数等，审视轻子味普适性和跃迁形状因子相关性。
中文摘要 AI 辅助
本文利用QCD光锥求和规则计算\(D_s^+ \to K^{*0}\)衰变的跃迁形状因子\(A_{1,2}(q^2)\)和\(V(q^2)\)，通过构建含常规流的关联函数，其中\(K^{*0}\)介子的 twist - 2 横向和纵向光锥分布振幅构成理论不确定性主要来源。基于此用轻锥谐振子模型构建这些分布振幅。在大反冲区域得到相关形状因子及比值，还预测了形状因子相关性及其比值。接着在整个物理\(q^2\)区域外推形状因子，计算了半轻子衰变\(D_s^+\to K^{*0}\ell^+\nu_{\ell}\)的衰变宽度和分支比，得到分支比及比值，提取了CKM矩阵元值，最后计算了\(D_s^+\to K^{*0} \ell^+\nu_{\ell}\)衰变的前后不对称参数。
英文摘要
In this paper, we calculate the transition form factors (TFFs) $A_{1,2}(q^2)$ and $V(q^2)$ of $D_s^+ \to K^{*0}$ decays by using the QCD light-cone sum rule (QCD LCSR) and constructing a correlation function containing the usual current, in which the twist-2 transverse and longitudinal light-cone distribution amplitudes (LCDAs) $ϕ^λ_{2;K^{*0}}(x,μ_0)$ with $λ=(\bot,\|)$ of the $K^{*0}$ meson constitute the main source of theoretical uncertainty. Based on this, we construct these LCDAs using the light-cone harmonic oscillator model. Subsequently, the TFFs obtained in the large recoil region are $A_{1}(0)=0.579_{-0.028}^{+0.024}$, $A_{2}(0)=0.414_{-0.023}^{+0.021}$, and $V(0)=0.830_{-0.020}^{+0.020}$, and the corresponding ratios are obtained to be $r_V=1.433_{-0.090}^{+0.110}$ and $r_2=0.715_{-0.067}^{+0.075}$. Furthermore, we predict the correlation of TFFs and their corresponding ratios. Then, we extrapolate the TFFs over the whole physical $q^2$-region and calculate the decay widths and branching fractions for the semileptonic decays $D_s^+\to K^{*0}\ell^+ν_{\ell}$. The results are $\mathcal{B}(D_s^+\to K^{*0}e^+ν_{e})=(2.05_{-0.16}^{+0.13})\times 10^{-3}$ and $\mathcal{B}(D_s^+\to K^{*0}μ^+ν_μ)=(1.95_{-0.15}^{+0.13})\times 10^{-3}$. Meanwhile, we calculated the branching fraction ratio $\mathcal{R}_{μ/e}^{K^{*0}}$ to be $0.950_{-0.002}^{+0.004}$. In addition, we extract values of the CKM matrix element, obtaining $|V_{cd}|_{(e\text{-Channel})} = 0.225_{-0.005}^{+0.005}$ and $|V_{cd}|_{(μ\text{-Channel})} = 0.227_{-0.004}^{+0.011}$. Finally, we calculated the forward-backward asymmetry parameters for the $D_s^+\to K^{*0} \ell^+ν_{\ell}$ decay.
