W-pair production in modified perturbation theory

TL;DR

This paper evaluates the modified perturbation theory's effectiveness in accurately predicting W-pair production processes at the ILC, demonstrating high precision agreement with traditional methods up to NNLO Breit-Wigner factors.

Contribution

It introduces and tests the application of modified perturbation theory for unstable particle processes, showing its high precision in comparison with Dyson-resummed approaches.

Findings

High-precision agreement with Dyson-resummed calculations at ILC energies

Modified perturbation theory achieves better than per-mille accuracy

Validation of MPT for processes involving unstable particles

Abstract

We examine capabilities of the modified perturbation theory (MPT) for description of the processes with productions and decays of fundamental unstable particles. We calculate total cross-section for $e^{+} e^{-} \to \gamma,Z \to W^{+} W^{-} \to 4f$ in a model with the Dyson-resummed and with the MPT-expanded up to the NNLO Breit-Wigner factors, and compare the outcomes. At the ILC energies a coincidence of the outcomes is detected with precision better than one per-mille.