Cabibbo angle anomalies and oblique corrections: The remarkable role of the vectorlike quark doublet

The combination of precise determinations of Vₔₒ and Vₔ₃ hints toward a violation of the Cabibbo-Kobayashi-Maskawa matrix first row unitarity at about 3 level. Conversely, the recent measurement of the W-boson mass by the CDF Collaboration exhibits significant tension with the Standard Model prediction, intensifying the conflict that may arise in models addressing the unitarity violation. We demonstrate that one vectorlike SU (2) ₋ doublet with mass of a few TeV mixing with light quarks and the top quark can simultaneously account for the two anomalies, without conflicting with flavor-changing phenomena and electroweak observables. Moreover, another tension in the value of the Cabibbo angle is also reported at the 3 level, between two determinations of Vₔₒ obtained from semileptonic K3 and leptonic K2 kaon decays. We show that the vectorlike doublet can be at the origin of this discrepancy and the substantial positive shift in the W-boson mass. This unique feature of the vectorlike quark doublet may render it a crucial puzzle piece in new physics scenarios addressing the Cabibbo-Kobayashi-Maskawa matrix unitarity problem. The model can be potentially probed in future colliders.