Hatton, D., Davies, C.T.H. , Lepage, G.P. and Lytle, A.T. (2019) Renormalizing vector currents in lattice QCD using momentum-subtraction schemes. Physical Review D, 100(11), 114513. (doi: 10.1103/PhysRevD.100.114513)
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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 ′ -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 ′ -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.
| Item Type: | Articles |
|---|---|
| Additional Information: | Authors for the HPWCD Collaboration. Funded by SCOAP3. |
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Lytle, Dr Andrew and Hatton, Dr Daniel and Davies, Professor Christine |
| Authors: | Hatton, D., Davies, C.T.H., Lepage, G.P., and Lytle, A.T. |
| College/School: | College of Science and Engineering > School of Physics and Astronomy |
| Research Group: | HPQCD Collaboration |
| Journal Name: | Physical Review D |
| Publisher: | American Physical Society |
| ISSN: | 2470-0010 |
| ISSN (Online): | 2470-0029 |
| Published Online: | 20 December 2019 |
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