k(T) factorization of exclusive processes
k(T) factorization of exclusive processes
复制标题
DOI：
10.1103/physrevd.67.034001
复制
发表时间：
2002-10
影响因子：
5
通讯作者：
M. Nagashima;Hsiang-nan Li
中科院分区：
文献类型：
--
作者：
M. Nagashima;Hsiang-nan Li
考虑$\ensuremath{\pi}{\ensuremath{\gamma}}^{*}\ensuremath{\rightarrow}\ensuremath{\gamma}(\ensuremath{\pi})$和$\stackrel{\ensuremath{\rightarrow}}{B}\ensuremath{\gamma}(\ensuremath{\pi})l\overline{\ensuremath{\nu}}.$，我们证明了微扰QCD （PQCD）中排他过程的${k}_{T}$因子分解定理，相关形式因子表示为冲击参数b空间中硬振幅与双部子介子波函数的卷积，b与部子横向动量共轭${k}_{T}.$。并通过共线胶子交换获得${k}_{T}$。具有适当路径的与b相关的双部子波函数是尺度不变的。硬振幅，定义为壳层外粒子的部分能级图与其共线近似之间的差异，也是规范不变的。我们比较了来自${k}_{T}$分解（PQCD方法）和共线分解（QCD分解方法）的两体非轻子B介子衰变的预测。
We prove the ${k}_{T}$ factorization theorem in perturbative QCD (PQCD) for exclusive processes by considering $\ensuremath{\pi}{\ensuremath{\gamma}}^{*}\ensuremath{\rightarrow}\ensuremath{\gamma}(\ensuremath{\pi})$ and $\stackrel{\ensuremath{\rightarrow}}{B}\ensuremath{\gamma}(\ensuremath{\pi})l\overline{\ensuremath{\nu}}.$ The relevant form factors are expressed as the convolution of hard amplitudes with two-parton meson wave functions in the impact parameter b space, b being conjugate to the parton transverse momenta ${k}_{T}.$ The point is that on-shell valence partons carry longitudinal momenta initially, and acquire ${k}_{T}$ through collinear gluon exchanges. The b-dependent two-parton wave functions with an appropriate path for the Wilson links are gauge-invariant. The hard amplitudes, defined as the difference between the parton-level diagrams of on-shell external particles and their collinear approximation, are also gauge-invariant. We compare the predictions for two-body nonleptonic B meson decays derived from ${k}_{T}$ factorization (the PQCD approach) and from collinear factorization (the QCD factorization approach).