Densities, parton distributions, and measuring the nonspherical shape of the nucleon

作     者：Gerald A. Miller 

作者机构：University of Washington Seattle Washington 98195-1560 USA 

出 版 物：《Physical Review C》 (物理学评论C辑：核物理学)

年 卷 期：2007年第76卷第6期

页      面：065209-065209页

核心收录：

学科分类：07[理学] 070202[理学-粒子物理与原子核物理] 0702[理学-物理学] 

主　　题：FRAGMENTATION FUNCTIONS LEPTOPRODUCTION POLARIZATION 

摘      要：Spin-dependent quark densities, matrix elements of specific density operators in proton states of definite spin-polarization, indicate that the nucleon may harbor an infinite variety of nonspherical shapes. We show that these matrix elements are closely related to specific transverse-momentum-dependent (TMD) parton distributions accessible in the angular dependence of the semi-inclusive processes ep→eπX and the Drell-Yan reaction pp→ll¯X. New measurements or analyses would allow the direct exhibition of the nonspherical nature of the proton.