Factorization theorem for Drell-Yan at low qT and transverse-momentum distributions on-the-light-cone
Factorization theorem for Drell-Yan at low qT and transverse-momentum distributions on-the-light-cone
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DOI：
10.1007/jhep07(2012)002
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发表时间：
2011-11
影响因子：
5.4
通讯作者：
M. G. Echevarria;Ahmad Idilbi;I. Scimemi
中科院分区：
文献类型：
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作者：
M. G. Echevarria;Ahmad Idilbi;I. Scimemi
利用有效的场论方法，导出了低q T下Drell-Yan过程的分解定理。在这个定理中，所有得到的量都是规范不变的，并强调了软函数及其减法的特殊作用。我们定义了不受光锥奇点影响的横动量相关部分分布函数（tmdpdf），而所有的Wilson线都是在光锥上定义的。我们在α s中明确地表明，通过对强子内的部分子的横向动量积分，可以从新定义的部分子TMDPDF得到部分子费曼PDF。我们在冲击参数空间中得到了TMDPDF的恢复表达式，因此也得到了横截面的恢复表达式。新定义的矩阵元素的普适性被摄动地建立到α s的一阶，分解定理被验证到α s的一阶，以及费曼和光锥量规之间的规范不变性。
We derive a factorization theorem for Drell-Yan process at low q T using effective field theory methods. In this theorem all the obtained quantities are gauge invariant and the special role of the soft function—and its subtraction thereof—is emphasized. We define transverse-momentum dependent parton distribution functions (TMDPDFs) which are free from light-cone singularities while all the Wilson lines are defined on-the-light-cone. We show explicitly to first order in α s that the partonic Feynman PDF can be obtained from the newly defined partonic TMDPDF by integrating over the transverse momentum of the parton inside the hadron. We obtain a resummed expression for the TMDPDF, and hence for the cross section, in impact parameter space. The universality of the newly defined matrix elements is established perturbatively to first order in α s. The factorization theorem is validated to first order in α s and also the gauge invariance between Feynman and light-cone gauges.