Leptophilic New Physics and the Cabibbo Angle Anomaly

Abstract

The Cabibbo Angle Anomaly, an apparent deficit in first-row CKM unitarity, can be addressed by leptophilic Standard Model extensions that generate new contributions to the Fermi constant and affect the determination of the CKM element $V_{ud}$. We focus on simplified models with this property, including the Standard Model extended by vectorlike leptons, by the singly charged scalar singlet, or by a leptophilic $Z^{\prime }$ boson.

Comments: 5 pages, 3 figures, Contribution to the 32nd Rencontres de Blois