Interpreting electroweak precision data including the W-mass CDF anomaly

We perform a global fit of electroweak data, finding that the anomaly in the W mass claimed by the CDF collaboration can be reproduced as a universal new-physics correction to the T parameter or vertical bar H-dagger D-mu H vertical bar(2) operator. Contributions at tree-level from multi-TeV new physics can fit the anomaly compatibly with collider bounds: we explore which scalar vacuum expectation values (such as a triplet with zero hypercharge), Z' vectors (such as a Z' coupled to the Higgs only), little-Higgs models or higher-dimensional geometries provide good global fits. On the other hand, new physics that contributes at loop-level must be around the weak scale to fit the anomaly. Thereby it generically conflicts with collider bounds, that can be bypassed assuming special kinematics like quasi-degenerate particles that decay into Dark Matter (such as an inert Higgs doublet or appropriate supersymmetric particles).

Automated summary

The study globally fits electroweak data and finds that new physics corrections can explain the anomaly in the W boson mass. Tree-level contributions from multi-TeV new physics can fit the anomaly compatibly with collider bounds, while loop-level contributions must be around the weak scale to fit the anomaly.