SMEFT Corrections to $Z$ Boson Decays

TL;DR

This paper calculates one-loop SMEFT corrections to Z boson decays, highlighting their comparable size to Standard Model corrections and their importance for future global fits of Wilson coefficients.

Contribution

It provides the first detailed computation of one-loop SMEFT corrections to Z decays, linking these to anomalous gauge couplings for precise phenomenological analysis.

Findings

Corrections are of order a few percent, similar to electroweak Standard Model corrections.

The results enable more accurate global fits of SMEFT Wilson coefficients.

The work connects Z decay observables with anomalous gauge couplings.

Abstract

We compute the one-loop corrections to $Z$ decay properties from dimension-6 operators in the Standard Model Effective Field Theory (SMEFT) that contribute also to anomalous 3-gauge boson couplings and examine the relative sensitivity of the two processes to the anomalous couplings. The size of the contributions is of order a few percent, of the same size as Standard Model electroweak corrections. This is part of a program of computing electroweak quantities to one-loop in the SMEFT: these calculations are needed for a future global fit to limit the coefficients of the dimension-six Wilson coefficients consistently at one loop.