Reevaluation of heavy-fermion-induced electron EDM at three loops

Abstract

Motivated by improved limits on electric dipole moments (EDMs), we revisit the three-loop light-by-light mechanism that transmits $CP$ violation from a heavy fermion to a light one. Applying it to the electron EDM induced by EDMs of heavier flavors, we find additional contributions at the order $m_e/m_{\mu }$ or $m_e/m_{\tau }$ that were missing before and that make the result 1.4 times larger. Consequently we improve bounds on the tau EDM, and update indirect limits on the muon EDM as well as charm and bottom quark color EDMs.

Comments: 8 pages, 2 figures