Radiative leptonic decays of B mesons in QCD
Radiative leptonic decays of B mesons in QCD
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DOI：
10.1103/physrevd.61.114510
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发表时间：
1999-11
影响因子：
5
通讯作者：
G. Korchemsky;D. Pirjol;T. Yan
中科院分区：
文献类型：
--
作者：
G. Korchemsky;D. Pirjol;T. Yan
我们计算了光子能量远大于QCD的重介子B + → γe + ν辐射轻子衰变的形状因子，其中排斥过程的微扰QCD方法可以与重夸克有效理论相结合.在这个区域中，形状因子可以可靠地以λ/Eγ的幂展开来获得。在这个扩展中的主导项显示了额外的自旋对称性，表现在矢量和轴向电流的形状因子相等。在此基础上，导出了B介子光锥波函数与硬散射振幅的卷积，并计算得到了单圈量级的扭转形状因子。形式为（αs π log 2 2 E ′）n的Sudakov二重代数被表示为所有阶.作为应用，我们提出了一种确定CKM质量元素的方法|VUB|从B和D辐射轻子衰变的光子谱的比较。
We compute the form factors parametrizing radiative leptonic decays of heavy mesons B + → γe + ν for photon energies much larger thanQCD, where per- turbative QCD methods for exclusive processes can be combined with the heavy quark effective theory. The form factors can be reliably obtained in this region in an expansion in powers of �/Eγ. The leading term in this ex- pansion displays an additional spin symmetry manifested in the equality of form factors of vector and axial currents. The leading twist form factors can be written as the convolution of the B meson light-cone wave function with a hard scattering amplitude, which is explicitly calculated to one-loop order. The Sudakov double logarithms of the form ( αs π log 2 2E � ) n are resummed to all orders. As an application we present a method for determining the CKM ma- trix element |Vub| from a comparison of photon spectra in B and D radiative leptonic decays.