Fits of the Electroweak Standard Model and Beyond using Gfitter

TL;DR

This paper revisits the global electroweak fit of the Standard Model using the new Gfitter package, incorporating Higgs search constraints and advanced statistical analysis, providing updated parameter estimates and exploring beyond Standard Model scenarios.

Contribution

Introduction of Gfitter, a new generic fitting package, enabling comprehensive electroweak fits with updated data and statistical methods, including constraints from Higgs searches and extended Higgs sectors.

Findings

Estimated Higgs boson mass: 116.4^{+18.3}_{-1.3} GeV

Strong coupling constant: 0.1193^{+0.0028}_{-0.0027}

SM p-value: 0.22

Abstract

The global fit of the Standard Model to electroweak precision data, routinely performed by the LEP electroweak working groups and others, has been revisited in view of (i) the development of the new generic fitting package, Gfitter, (ii) the insertion of constraints from direct Higgs searches at LEP and Tevatron, and (iii) a more thorough statistical interpretation of the results. This paper describes the Gfitter project, and presents state-of-the-art results for the global electroweak fit in the Standard Model, and for a model with an extended Higgs sector. Example results are an estimation of the mass of the Higgs boson (M_H = 116.4^{+18.3}_{-1.3} GeV) and a forth-order result for the strong coupling strength (alpha_S(M_Z^2) = 0.1193^{+0.0028}_{-0.0027}(exp)+/-0.0001(theo)). Using toy Monte Carlo techniques the p-value of the SM has been determined (p=0.22). As an example of a New Physics model constraints are derived for the Two Higgs Doublet Model of Type-II using observables from the B and K physics sectors.