INPAC, Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China and Center for High-Energy Physics, Peking University, Beijing 100080, People's Republic of China and Maryland Center for Fundamental Physics, University of Maryland, College Park, Maryland 20742, USA.
Phys Rev Lett. 2013 Sep 13;111(11):112002. doi: 10.1103/PhysRevLett.111.112002. Epub 2013 Sep 10.
The total gluon helicity in a polarized proton, measurable in high-energy scattering, is shown to be the large momentum limit of a gauge-invariant but nonlocal, frame-dependent gluon spin E × A⊥ in QCD. This opens a door for a nonperturbative calculation of this quantity in lattice QCD and also justifies using free-field expressions in the light-cone gauge as physical observables.
在高能散射中可测量的极化质子中的总胶子螺旋度被证明是 QCD 中规范不变但非局域、与框架相关的胶子自旋 E×A⊥在大动量极限下的表现。这为在格点 QCD 中对这个量进行非微扰计算开辟了一扇大门，也证明了在光锥规范中使用自由场表达式作为物理可观测量的合理性。
