R(s) and Z decay in order \alpha_s^4: complete results

TL;DR

This paper presents complete order 4 calculations of decay rates and cross sections in electron-positron annihilation, providing the first full 4 predictions for Z-boson hadronic decay and R(s).

Contribution

It delivers the first complete 4 order theoretical predictions for Z-boson decay rates and R(s), combining axial and vector singlet contributions.

Findings

First complete 4 order predictions for Z decay

Accurate calculations of electron-positron annihilation cross sections

Enhanced precision in testing the Standard Model

Abstract

We report on our calculation of the order \alpha_s^4 axial singlet contributions for the decay rates of the Z-boson as well as the vector singlet contribution to the cross section for electron-positron annihilation into hadrons. Together with recently finished O(\alpha_s^4) calculations of the non-signlet corrections [1,2], the new results directly lead us to the first complete O(\alpha_s^4) predictions for the total hadronic decay rate of the Z-boson and the ratio R(s).