NLO Higgs Effective Field Theory and kappa-framework

TL;DR

This work develops a gauge-invariant, renormalizable framework for Standard Model deviations using a dimension-6 EFT extended to next-to-leading order, thereby generalizing the LO $\upkappa$ framework. By organizing the amplitude into SM-like $\mathcal{O}(4)$ structures plus dimension-6 insertions and carefully renormalizing Wilson coefficients (with scheme choices such as $G_F$ or $\alpha$), the authors provide a consistent path to extract Higgs couplings and probe UV completions. They implement a comprehensive renormalization program (including Ward identities, Dyson resummation, and 1PI/1PR contributions) and apply it to Higgs decays and electroweak precision data, establishing connections to Warsaw-basis operators and oblique parameters. The framework enables model-independent fits to high-precision Higgs and EW measurements, facilitating robust constraints on BSM physics as experimental sensitivity improves.

Abstract

A consistent framework for studying Standard Model deviations is developed. It assumes that New Physics becomes relevant at some scale beyond the present experimental reach and uses the Effective Field Theory approach by adding higher-dimensional operators to the Standard Model Lagrangian and by computing relevant processes at the next-to-leading order, extending the original kappa-framework.

Figures (1)

• Figure 1: Doubly-contracted WST identities with two external gauge bosons. Gray circles denote the sum of the needed Feynman diagrams at any given order in EFT.