Vanishing or non-vanishing rainbow? Reduction formulas of electric dipole moment
arXiv:2106.03384 · doi:10.1007/JHEP10(2021)237
Abstract
In this paper, we derive a simplified formula of electric dipole moments (EDMs) of a fermion. In the Standard Model, it is well-known that non-trivial cancellations between some rainbow-type diagrams induced by boson exchanges occur in the calculation of the neutron EDM at the two-loop level due to the gauge symmetry. The fermion self-energy and the vertex correction are related through the Ward-Takahashi identity, and this relation causes the exact cancellation of the EDM. We derive EDM formulas for a more general setup by introducing the form factors for the fermion self-energy and the vertex correction so that the derived formulas can be applicable to a larger class of models. We conclude that the non-zero EDM contributions are induced from rainbow-type diagrams with the chirality flipping effects for internal fermions. We also discuss the other possible generalization of the EDM calculation which is applicable to the other classes of models.
arXiv comment23 pages, 7 figures, 2 tables, the version published in JHEP
References in corpus (13)
- Verifiable Radiative Seesaw Mechanism of Neutrino Mass and Dark Matter
- Electric dipole moments as probes of new physics
- Measurement of the permanent electric dipole moment of the neutron
- Searching for New Physics beyond the Standard Model in Electric Dipole Moment
- Measurement of the electron's electric dipole moment using YbF molecules: methods and data analysis
- A new method for determining the quark-gluon vertex
- Loop-Less Electric Dipole Moment of the Nucleon in the Standard Model
- A note on Majorana neutrinos, leptonic CKM and electron electric dipole moment
- Electric Dipole Moments of Leptons in the Presence of Majorana Neutrinos
- Electric Dipole Moments in the Minimal Scotogenic Model
- The Neutron EDM in the SM : A Review
- Charged Lepton Electric Dipole Moments from TeV Scale Right-handed Neutrinos
- Electric dipole moments in the extended scotogenic models