A complete next-to-leading order QCD description of resonant $Z'$ production and decay into $t\bar t$ final states

TL;DR

This paper provides a comprehensive NLO QCD calculation for resonant Z' production and decay into top-antitop pairs at the LHC, including top decays and interference effects, crucial for accurate experimental analysis.

Contribution

It introduces the first NLO QCD computation of interference between Z' signals and QCD background, including new one-loop amplitudes, enhancing precision in resonance studies.

Findings

QCD corrections significantly affect Z' signal predictions.

Interference effects at NLO alter exclusion limits.

New one-loop amplitudes are essential for accurate modeling.

Abstract

We discuss QCD radiative corrections to the production of a heavy neutral resonance $Z'$ at the LHC assuming that it decays into a $ t\bar t$ final state. Compared to previous studies, our computation includes top quark decays as well as interference between the $Z'$ signal process and the QCD $t \bar t$ background. The interference contribution appears for the first time at next-to-leading order (NLO) QCD and requires new one-loop amplitudes that are not present when signal and background are treated separately. We describe some examples of how QCD radiative corrections may influence both the exclusion limits and studies of properties of the new resonance, once it is discovered.