Effective charge from lattice QCD

• 作者: C.D.Roberts C.Mezrag D.Binosi F.De Soto J.-L.Zhang J.Papavassiliou J.Rodríguez-Quintero J.Segovia S.Zafeiropoulos Z.-F.Cui
• 来源期刊: 中国物理C（英文版）
• 年，卷（期）: 2020,（8）
• 页码范围: 23-32
• 页数: 10页
• 语种: 英文
• DOI: 10.1088/1674-1137/44/8/083102

摘要

Using lattice configurations for quantum chromodynamics (QCD) generated with three domain-wall fermions at a physical pion mass,we obtain a parameter-free prediction of QCD's renormalisation-group-invariant process-independent effective charge,(α)(k2).Owing to the dynamical breaking of scale invariance,evident in the emergence of a gluon mass-scale,m0 =0.43(1)GeV,this coupling saturates at infrared momenta: (α)(0)/π =0.97(4).Amongst other things: (α)(k2) is almost identical to the process-dependent (PD) effective charge defined via the Bjorken sum rule;and also that PD charge which,employed in the one-loop evolution equations,delivers agreement between pion parton distribution functions computed at the hadronic scale and experiment.The diversity of unifying roles played by (α)(k2) suggests that it is a strong candidate for that object which represents the interaction strength in QCD at any given momentum scale;and its properties support a conclusion that QCD is a mathematically well-defined quantum field theory in four dimensions.