The global electroweak Standard Model fit after the Higgs discovery

TL;DR

This paper updates the global electroweak fit within the Standard Model after the Higgs discovery, confirming its consistency and precision predictions without signs of new physics, and discusses future collider prospects.

Contribution

It provides the first over-constrained electroweak fit using known parameters post-Higgs discovery, enhancing precision and testing the SM's validity.

Findings

W boson mass and weak mixing angle predictions match and surpass direct measurements.

S, T, U parameters are consistent with SM expectations.

No evidence of new physics is observed.

Abstract

We present an update of the global Standard Model (SM) fit to electroweak precision data under the assumption that the new particle discovered at the LHC is the SM Higgs boson. In this scenario all parameters entering the calculations of electroweak precision observalbes are known, allowing, for the first time, to over-constrain the SM at the electroweak scale and assert its validity. Within the SM the W boson mass and the effective weak mixing angle can be accurately predicted from the global fit. The results are compatible with, and exceed in precision, the direct measurements. An updated determination of the S, T and U parameters, which parametrize the oblique vacuum corrections, is given. The obtained values show good consistency with the SM expectation and no direct signs of new physics are seen. We conclude with an outlook to the global electroweak fit for a future e+e- collider.