An effective field theory approach to the electroweak corrections at LEP energies

TL;DR

This paper employs an effective field theory framework to analytically compute and fit electroweak corrections at LEP energies, achieving precise predictions for key processes with minimal error.

Contribution

It introduces an EFT-based method to accurately model electroweak corrections at LEP energies, including finite mass effects, and validates the approach through data fitting and precise cross-section predictions.

Findings

EFT reproduces dominant electroweak corrections analytically.

Fitted effective couplings match LEP1/SLD data well.

Predicted cross sections agree within 1% with experimental results.

Abstract

In the framework of the effective field theory (EFT) we discuss the electroweak (EW) corrections at LEP energies. We obtain the effective Lagrangian in the large m_t limit, and reproduce analytically the dominant EW corrections to the LEP2 processes e+ e- --> gamma Z and e+ e- --> Z Z. To include effects of finite top-quark and Higgs masses, we use the effective Lagrangian at tree level and fit LEP1/SLD observables with four arbitrary parameters, plus alpha_s(m_Z). The EFT approach works remarkably well. Using the effective couplings determined from the fit, and tree-level EFT formulae, we predict the cross sections for e+ e- --> Z Z, gamma Z at a level better than 1%.