论文标题
底部介子的半衰减衰减的相对论描述
Relativistic description of the semileptonic decays of bottom mesons
论文作者
论文摘要
半雌科$ b $，$ b_s $和$ b_c $ meson衰减的形式是根据QCD中的QCD方法的相对论夸克模型的框架计算的。它们是通过介子波函数的重叠积分来表达的。所有相对论效应都始终如一地考虑到。动量转移$ q^2 $形式的行为在整个可访问的运动范围内确定。我们不使用任何外推，重夸克$ 1/m_q $膨胀或模型假设，以实现形状的形状。给出了形式因素的方便分析表达式，这非常准确地重现了我们计算的数值结果。根据这些形式和螺旋形式主义，计算了底部介子的各种半衰减衰变的差异和总分支分数。前向反复不对称的平均值$ \ langle a_ {fb} \ rangle $，Lepton-side convexity参数$ \ langle c^\ ell_ {f} \ langle $，longitudinal $ \ langle $ \ langle p^\ ell_ ell_ ell_ {l} p^\ ell_ {t} \ rangle $ $ yplational $ $ \ langle $ \ langle f_ {l} \ rangle $用于最终状态矢量梅森。我们对所获得的预测与基于协变光夸克模型的计算进行了详细的比较，并将其与可用的晶格QCD和实验数据对抗。已经发现，尽管这两个模型都预测了总分支部分的近距值，但差分分布和前后不对称和极化参数差异很大，尤其是在重度半衰减的衰减中。我们确定可观察到的测量可以帮助区分模型。
The form factors of the semileptonic $B$, $B_s$ and $B_c$ meson decays are calculated in the framework of the relativistic quark model based on the quasipotential approach in QCD. They are expressed through the overlap integrals of the meson wave function. All relativistic effects are consistently taken into account. The momentum transfer $q^2$ behavior of form factors is determined in the whole accessible kinematical range. We do not use any extrapolations, heavy quark $1/m_Q$ expansion or model assumptions about the shape of form factors. Convenient analytic expressions of the form factors are given, which very accurately reproduce the numerical results of our calculation. On the basis of these form factors and helicity formalism, the differential and total branching fractions of various semileptonic decays of bottom meson are calculated. The mean values of the forward-backward asymmetry $\langle A_{FB}\rangle$, lepton-side convexity parameter $\langle C^\ell_{F}\rangle$, longitudinal $\langle P^\ell_{L}\rangle$ and transverse $\langle P^\ell_{T}\rangle$ polarization of the charged lepton, and the longitudinal polarization fraction $\langle F_{L}\rangle$ for final-state vector meson are also evaluated. We present a detailed comparison of the obtained predictions with the calculations based on the covariant light-front quark model and confront them to available lattice QCD and experimental data. It is found that although both models predict close values of the total branching fractions, the differential distributions and forward-backward asymmetry and polarization parameters differ significantly, especially for the heavy-to-light semileptonic decays. We identify observables which measurement can help to discriminate between models.
