Precision predictions for Z'-production at the CERN LHC: QCD matrix elements, parton showers, and joint resummation

TL;DR

This paper enhances the theoretical predictions for Z' boson production at the LHC by implementing advanced QCD calculations and resummation techniques, leading to more accurate cross section estimates and reduced uncertainties.

Contribution

The paper introduces a new implementation of Z' boson production in the MC@NLO generator and applies joint resummation, improving prediction accuracy over traditional methods.

Findings

Excellent agreement between improved predictions for spectra and cross sections.

Significant shortcomings identified in PYTHIA shower predictions.

Theoretical uncertainties are reduced to below 10%.

Abstract

We improve the theoretical predictions for the production of extra neutral gauge bosons at hadron colliders by implementing the Z' bosons in the MC@NLO generator and by computing their differential and total cross sections in joint p_T and threshold resummation. The two improved predictions are found to be in excellent agreement with each other for mass spectra, p_T spectra, and total cross sections, while the PYTHIA parton and ``power'' shower predictions usually employed for experimental analyses show significant shortcomings both in normalization and shape. The theoretical uncertainties from scale and parton density variations and non-perturbative effects are found to be 9%, 8%, and less than 5%, respectively, and thus under good control. The implementation of our improved predictions in terms of the new MC@NLO generator or resummed K factors in the analysis chains of the Tevatron and LHC experiments should be straightforward and lead to more precise determinations or limits of the Z' boson masses and/or couplings.