文献类型：期刊文献

中文题名：Single Transverse Spin Asymmetries at Parton Level

英文题名：Single Transverse Spin Asymmetries at Parton Level

作者：Cao Hui-Geng[1];Ma Jian-Ping[2];Sang Hua-Zheng[2,3]

机构：[1]Beijing Univ Civil Engn & Architecture, Sch Sci, Beijing 100044, Peoples R China;[2]Acad Sinica, Inst Theoret Phys, Beijing 100190, Peoples R China;[3]E China Univ Sci & Technol, Sch Sci, Inst Modern Phys, Shanghai 200237, Peoples R China

年份：2010

卷号：53

期号：2

起止页码：313

中文期刊名：Communications in Theoretical Physics

外文期刊名：COMMUNICATIONS IN THEORETICAL PHYSICS

收录：CSTPCD;;Scopus;WOS:【SCI-EXPANDED(收录号:WOS:000275133900021)】；CSCD:【CSCD2011_2012】；PubMed;

基金：Supported by National Natural Science Foundation of China under Grant Nos. 10721063, 10575126, and 10975169

语种：英文

中文关键词：single spin asymmetries; QCD factorization

外文关键词：single spin asymmetries; QCD factorization

摘要：Two factorization approaches have been proposed for single transverse spin asymmetries. One is the cofiinear factorization, the other is the transverse-momentum-dependent factorization. They have been previously derived in a formal way by using diagram expansion at hadron level. If the two factorizations hold or can be proven, they should also hold when we replace hadrons with patton states. We examine these two factorizations at patton level with massless partons. It is nontrivial to generate these asymmetries at parton level with massless patrons because the asymmetries require helicity-flip and nonzero absorptive parts in scattering amplitudes. By constructing suitable patton states with massless partons we derive the two factorizations for the asymmetry in Drell-Yan processes. It is found from our results that the collinear factorization derived at parton level is not the same as that derived at hadron level. Our results with massless partons confirm those derived with single massive parton state in our previous works.
Two factorization approaches have been proposed for single transverse spin asymmetries. One is the collinear factorization, the other is the transverse-momentum-dependent factorization. They have been previously derived in a formal way by using diagram expansion at hadron level. If the two factorizations hold or can be proven, they should also hold when we replace hadrons with parton states. We examine these two factorizations at parton level with massless partons. It is nontrivial to generate these asymmetries at parton level with massless partons because the asymmetries require helicity-flip and nonzero absorptive parts in scattering amplitudes. By constructing suitable parton states with massless partons we derive the two factorizations for the asymmetry in Drell-Yan processes. It is found from our results that the collinear factorization derived at parton level is not the same as that derived at hadron level. Our results with massless partons confirm those derived with single massive parton state in our previous works.