Renormalizing vector currents in lattice QCD using momentum-subtraction schemes

2019/09/30 by D. Hatton, C. T. H. Davies, G. P. Lepage +2
Mathematics · Physics and Astronomy · #High-Energy Particle Collisions Research #Lattice (music) #Lattice QCD #Lattice field theory #Mathematics #Particle physics #Physics #Physics of Superconductivity and Magnetism #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum electrodynamics #Statistical physics #Subtraction #hep-lat

paper · pdf · doi:10.1103/physrevd.100.114513

published as Phys. Rev. D 100, 114513 (2019) · Minor changes to the text and references added. Version accepted by Phys. Rev. D

openalex created_date 2019/09/12 · arxiv created 2019/11/28 · openalex publication_date 2019/12/20 · arxiv updated 2019/12/25 · openalex updated_date 2026/08/05

Abstract

We examine the renormalization of flavor-diagonal vector currents in lattice QCD with the aim of understanding and quantifying the systematic errors from nonperturbative artifacts associated with the use of intermediate momentum-subtraction schemes. Our study uses the highly improved staggered quark action on gluon-field configurations that include n_f=2+1+1 flavors of sea quarks, but our results have applicability to other quark actions. Renormalization schemes that make use of the exact lattice vector Ward-Takahashi identity for the conserved current also have renormalization factors, Z_V, for nonconserved vector currents that are free of contamination by nonperturbative condensates. We show this by explicit comparison of two such schemes: that of the vector form factor at zero momentum transfer and the RI-SMOM momentum-subtraction scheme. The two determinations of Z_V differ only by discretization effects (for any value of momentum transfer in the RI-SMOM case). The RI^\ensuremath'-MOM scheme, although widely used, does not share this property. We show that Z_V determined in the standard way in this scheme has O(1%) nonperturbative contamination that limits its accuracy. Instead we define an RI^\ensuremath'-MOM Z_V from a ratio of local to conserved vector current vertex functions and show that this Z_V is a safe one to use in lattice QCD calculations. We also perform a first study of vector current renormalization with the inclusion of quenched QED effects on the lattice using the RI-SMOM scheme.

Citations

• Lattice study of semileptonic form factors with twisted boundary conditions
• Non-perturbative renormalisation of composite operators in lattice QCD
• Prediction of theDs*Width from a Calculation of its Radiative Decay in Full Lattice QCD
• Perturbation theory versus simulation for tadpole improvement factors in pure gauge theories
• Renormalization Constants of Quark Operators for the Non-Perturbatively Improved Wilson Action
• Renormalization of quark bilinear operators in a momentum-subtraction scheme with a nonexceptional subtraction point