Pushing Higgs Effective Theory over the Edge

TL;DR

This paper investigates the limitations of dimension-6 operators in effective field theories for Higgs physics at the LHC, proposing improvements through squared contributions and simplified models with heavy scalars.

Contribution

It demonstrates that including squared dimension-6 terms enhances model accuracy and explores scalar extensions to better match LHC Higgs data.

Findings

Including squared dimension-6 terms improves agreement with full models.

Heavy scalar models can enhance predictions but introduce new deviations.

Virtuality-related observables benefit from scalar extensions at high energies.

Abstract

Based on a vector triplet model we study a possible failure of dimension-6 operators in describing LHC Higgs kinematics. First, we illustrate that including dimension-6 contributions squared can significantly improve the agreement between the full model and the dimension-6 approximation, both in associated Higgs production and in weak-boson-fusion Higgs production. Second, we test how a simplified model with an additional heavy scalar could improve the agreement in critical LHC observables. In weak boson fusion we find an improvement for virtuality-related observables at large energies, but at the cost of sizeable deviations in interference patterns and angular correlations.