The decays of on-shell and off-shell polarized gauge bosons into massive quark pairs at NLO QCD

TL;DR

This paper analyzes the decay distributions of polarized gauge bosons into massive quark pairs at NLO QCD, emphasizing the importance of quark mass effects in off-shell decays relevant to Higgs processes.

Contribution

It provides a detailed calculation of decay distributions including finite quark masses for off-shell gauge boson decays at NLO QCD, extending previous massless approximations.

Findings

Finite quark mass effects are significant in off-shell decay distributions.

The decay angle distributions depend on the off-shellness of the gauge boson.

Results are relevant for precise Higgs decay analyses.

Abstract

We discuss the polar angle decay distribution in the decay of on-shell and off-shell polarized (W,Z) gauge bosons into massive quark pairs. In particular for the off-shell decays in $H \to (W,Z) + (W^\ast,Z^\ast) (\to q_1\bar q_2)$ it is important to keep the masses of the charm and bottom quarks at their finite values since the scale of the problem is not set by $m_{W,Z}^2$ but by the off-shellness of the gauge boson which varies in the range $(m_1+m_2)^2 \le q^2 \le (m_H-m_{W,Z})^2$.