Constraining CP-violating electron-gluonic operators

• Main Authors: Kingman Cheung, Wai-Yee Keung, Ying-nan Mao, Chen Zhang
• Format: Article
• Language: English
• Published: SpringerOpen 2019-07-01
• Series: Journal of High Energy Physics
• Subjects: CP violation; Beyond Standard Model; Discrete Symmetries; Effective Field Theories
• Online Access: http://link.springer.com/article/10.1007/JHEP07(2019)074

Abstract We present an analysis of constraints on two types of CP-odd electron-gluonic operators (ēiγ 5 e)G μν a G aμν and e ¯ e G μ ν a G ∼ a μ ν $$ \left(\overline{e}e\right){G}_{\mu \nu}^a{\overset{\sim }{G}}^{a\mu \nu } $$ from current and future electric dipole moment (EDM) experiments. The recent result from the ACME experiment using ThO molecules is used to derive an impressive lower bound on the effective scale for (ēiγ 5 e)G μν a G aμν at 8 TeV, assuming a QCD one-loop factor and no helicity suppression from new physics. One interesting aspect is that (ēiγ 5 e)G μν a G aμν contributes to the observable EDM in ThO experiment mainly through CP-odd electron-nucleon interaction rather than direct electron EDM which arises from three-loop running and matching. For e ¯ e G μ ν a G ∼ a μ ν $$ \left(\overline{e}e\right){G}_{\mu \nu}^a{\overset{\sim }{G}}^{a\mu \nu } $$ the current bound is much weaker and suffers from large uncertainties. We also discuss the QCD running and matching for the CP-odd electron-gluonic operators and give an estimate of the relevant nucleon matrix elements and uncertainties that are needed in the calculation.