Electric dipole moments as probes of the RD(*) anomaly

Abstract

The measurements of the lepton flavor universality (LFU) in B(B¯→D(*)lν¯) indicate a significant deviation from the standard model prediction at a 3–4σ level, revealing a violation of the LFU (RD(*) anomaly). It is known that the RD(*) anomaly can be easily accommodated by an SU(2)L-singlet vector leptoquark (LQ) coupled primarily to third-generation fermions, whose existence is further motivated by a partial gauge unification. In general, such a LQ naturally leads to additional CP-violating phases in the LQ interactions. In this paper, we point out that the current RD(*) anomaly prefers the CP-violating interaction although B(B¯→D(*)lν¯) are CP-conserving observables. The CP-violating LQ predicts a substantial size of the bottom-quark electric dipole moment (EDM), the chromo-EDM, and also the tau-lepton EDM. Eventually at low energy, the nucleon and electron EDMs are radiatively induced. Therefore, we conclude that the RD(*) anomaly with the SU(2)L-singlet vector LQ provides unique predictions: neutron and proton EDMs with opposite signs and a magnitude of O(10−27) e cm, and suppressed electron EDM. Furthermore, we show that a similar EDM pattern is predicted in an SU(2)L-doublet scalar LQ scenario that can accommodate the RD(*) anomaly as well. These EDM signals could serve as crucial indicators in future experiments. Published by the American Physical Society 2024