Publications
Publication Information
| Title | Short flow-time coefficients of CP-violating operators |
| Authors | Matthew Rizik, Andrea Shindler |
| JLAB number | JLAB-THY-20-3191 |
| LANL number | arXiv:2005.04199 |
| Other number | DOE/OR/23177-4968 |
| Document Type(s) | (Journal Article) |
| Associated with EIC: | No |
| Supported by Jefferson Lab LDRD Funding: | No |
| Funding Source: | Nuclear Physics (NP) |
|
Journal Compiled for Physical Review D Volume 102 Page(s) 034509 Refereed | |
| Publication Abstract: | Measurements of a permanent neutron electric dipole moment (EDM) potentially probe Beyond- the-Standard Model (BSM) sources of CP-violation. At low energy the CP-violating BSM inter- actions are parametrized by flavor-conserving CP-violating operators of dimension higher than 4. QCD calculations of the nucleon matrix elements of these operators are required to fully reconstruct the sources and magnitudes of the different CP-violating contributions to the nucleon EDM. In this work we study the quark-chromo electric dipole moment (qCEDM) operator and the three-gluon Weinberg operator. The non-perturbative determination, using lattice QCD, of the nucleon matrix elements of these CP-violating operators is hampered by their short-distance behavior. Under renor- malization these operators mix with lower dimensional operators, which induces power divergences in the lattice spacing, as the continuum limit is approached. We study the short-distance behavior of the qCEDM and the Weinberg operators using the gradient flow. We perform a short flow time expansion and determine, in perturbation theory, the expansion coefficients of the linearly-divergent terms stemming from the mixing with the pseudoscalar density and the topological charge, confirm- ing the expectations of the operator product expansion. We introduce a new method to perform calculations at non-zero flow-time for arbitrary values of the external momenta. This method allows us to work in four dimensions for most of the calculations described in this paper, avoiding the com- plications associated with defining gamma_5 in generic d dimensions. We show that leading contributions in the external momenta can be reproduced by defining ?5 using the t Hooft-Veltman-Breitenlohner- Maison scheme. |
| Experiment Numbers: | other |
| Group: | THEORY CENTER |
| Document: | |
| DOI: | https://doi.org/10.1103/PhysRevD.102.034509 |
| Accepted Manuscript: | PhysRevD.102.034509.pdf |
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