EWPD in the SMEFT to dimension eight

TL;DR

This paper calculates and provides interpolation tables for dimension-eight corrections in SMEFT affecting LEP electroweak data, highlighting their importance for accurate theoretical predictions and model analysis.

Contribution

It introduces the first comprehensive calculation of dimension-eight SMEFT corrections to LEP data and provides accessible interpolation tables for their application.

Findings

Dimension-eight corrections significantly impact LEP observables.

Neglecting these corrections introduces theoretical errors in SMEFT analyses.

Interpolation tables enable straightforward inclusion of these effects in future studies.

Abstract

We calculate the $\mathcal{O}(\langle H^{\dagger} H \rangle^{2} / \Lambda^{4} )$ corrections to LEP electroweak precision data using the geometric formulation of the Standard Model Effective Field Theory (SMEFT). We report our results in simple-to-use interpolation tables that allow the interpretation of this data set to dimension eight for the first time. We demonstrate the impact of these previously unknown terms in the case of a general analysis in the SMEFT, and also in the cases of two distinct models matched to dimension eight. Neglecting such dimension-eight corrections to LEP observables introduces a theoretical error in SMEFT studies. We report some preliminary studies defining such a theory error, explicitly demonstrating the effect of previously unknown dimension-eight SMEFT corrections on LEP observables.