Flavorful Electroweak Precision Observables in the Standard Model Effective Field Theory

TL;DR

This paper calculates next-to-leading order corrections to electroweak precision observables within an effective field theory framework, revealing how flavor structure influences limits on 4-fermion operators beyond the Standard Model.

Contribution

It provides the first detailed computation of NLO corrections to EWPO from flavor non-universal 4-fermion interactions in EFT, highlighting flavor dependence.

Findings

Limits on EFT coefficients depend strongly on flavor structure.

Next-to-leading order corrections significantly impact constraints.

Flavor non-universal interactions alter electroweak precision bounds.

Abstract

Electroweak precision observables (EWPO) measured at the W and Z poles provide stringent limits on possible beyond the Standard Model physics scenarios. In an effective field theory (EFT) framework, the next-to-leading order QCD and electroweak results for EWPO yield indirect limits on possible 4-fermion operators that do not contribute to the observables at tree level. Here we calculate the next-to-leading corrections to EWPO induced by flavor non-universal 4-fermion interactions and find that the extracted limits on EFT coefficients have a strong dependence on the flavor structure of the 4-fermion operators.