Modified perturbation theory for angular distribution in W-pair production

TL;DR

This paper evaluates the modified perturbation theory's effectiveness in accurately describing W-pair production and decay in electron-positron collisions, demonstrating high precision at ILC energies.

Contribution

It introduces a modified perturbation theory approach for W-pair production, achieving near-exact results at NNLO in a Dyson-resummed unstable particle model.

Findings

Results match exact calculations at ILC energies within per-mille accuracy.

Modified perturbation theory effectively describes angular distributions in W-pair production.

High precision achieved at NNLO approximation.

Abstract

We examine the capabilities of the modified perturbation theory (MPT) for description of $W$-pair production and decay in $e^{+} e^{-}$ annihilation. In a model with Dyson-resummed propagators of unstable particles, we calculate even and odd contributions to the distribution in the cosine of the $W^{-}$ production angle relative to the $e^{-}$ beam. On comparing the results of calculations in the NNLO approximation of MPT with the exact results in the model, a coincidence of outcomes at the ILC energies is detected at the per-mille level.