论文标题
$λ_b^0 $衰减在夸克模型中的重夸克对称性
Heavy quark symmetry of $Λ_b^0$ decays in quark models
论文作者
论文摘要
我们基于$λ_b^0 \toλ_c^+ell^+ellineLlineν_\ ell〜（\ ell = e，ell = e，μ，μ，μ，τ）$的衰减，研究了使用均质袋模型（HBM）和轻Quark模型（LFQM）的重夸克对称性。特别是，我们计算重夸克扩展中的各种参数，包括伊斯古尔的函数及其一阶校正。 HBM中的参数来自质谱，而LFQM中的参数则受到重夸克对称性的严格约束，赋予了我们结果的预测能力。我们明确地获得该$ {\ cal b}（λ_b^0 \toλ_c^+e^ - \overlineν_e）=（5.69 \ pm 0.58，5.35 \ pm 0.50）$，$ {\ cal b} $ 5.33 \ pm 0.49）$，和$γ（λ_b^0 \toλ_c^+τ^ - \overlineν_τ）/γ（λ_b^0 \toλ_c^+μ^ - \ usive usize^ - \ overlineC^ - +overlineLlineLlineLlineLlineLlineLlineLlineLlineLlineLlineLlineLlineChim =（0.3243 LFQM）。我们在两个模型中分支分数的结果与实验数据和晶格QCD计算很好。此外，我们发现硬透明的校正将分支的分数降低到$ 10 \％$。
We study the heavy quark symmetry with the homogeneous bag model (HBM) and light-front quark model (LFQM) based on the decays of $Λ_b^0\toΛ_c^+\ell^-\overlineν_\ell~(\ell=e,μ,τ)$. In particular, we calculate various parameters in the heavy quark expansions, including the Isgur-Wise functions and their first order corrections. The parameters in the HBM are fitted from the mass spectra, while the ones in the LFQM are tightly constrained by the heavy quark symmetry, granting the predictive power of our results. We explicitly obtain that ${\cal B}(Λ_b^0\toΛ_c^+e^-\overlineν_e)=(5.69\pm 0.58, 5.35\pm 0.50)$, ${\cal B}(Λ_b^0\toΛ_c^+μ^-\overlineν_μ)=(5.67\pm 0.58 $, $5.33\pm 0.49)$, and $Γ(Λ_b^0\toΛ_c^+τ^-\overlineν_τ)/Γ(Λ_b^0\toΛ_c^+μ^-\overlineν_μ)=(0.3243\pm 0.0126$, $ 0.3506\pm 0.0046)$ for the numerical values of (HBM, LFQM). Our results of the branching fractions in both models agree well with the experimental data and lattice QCD calculations. In addition, we find that the hard gluon corrections decrease the branching fractions around $10\%$.
