In this paper, we investigate the tree-dominated ( and ) decays in the Standard Model with the relevant form factors obtained in the light-front quark model. These decays involve much more helicity states relative to the corresponding and decays, and moreover, the contribution of longitudinal polarization mode ( meson) is relatively small, , compared with the corresponding meson decays. We have also computed the branching fraction, lepton spin asymmetry, forward-backward asymmetry, and ratio . Numerically, the branching fractions of decays are at the level of and are hopeful to be observed by LHC and Belle-II experiments. The ratios have relatively small theoretical uncertainties and are close to each other, , which are a bit different from the predictions in some previous works. The future measurements are expected to make tests on these predictions.

中文翻译：

---

诱变研究

在本文中，我们调查了以树为主的 （ 和 ）在标准模型中的衰减以及在光前夸克模型中获得的相关形状因数。相对于相应的衰变，这些衰变涉及更多的螺旋状态 和 衰变，而且，纵向极化模式（贡献介子）相对小，，与相应的比较介子衰变。我们还计算了分支分数，轻子自旋不对称性，前后不对称性和比率。从数值上讲，衰变处于LHC和Belle-II实验的水平，并有望被观察到。这些比率具有相对较小的理论不确定性，并且彼此接近，，与之前的一些作品中的预测有些不同。预期未来的测量将对这些预测进行测试。