t tbar W and t tbar Z Hadroproduction at NLO accuracy in QCD with Parton Shower and Hadronization effects

TL;DR

This paper provides advanced theoretical predictions for the production of top-antitop pairs with W and Z bosons at the LHC, integrating NLO QCD calculations with parton shower and hadronization effects.

Contribution

It introduces a method to match NLO QCD computations with parton shower simulations for t tbar W and Z production at the LHC using PowHel and POWHEG-BOX frameworks.

Findings

Predictions include dilepton and trilepton decay channels.

Results are relevant for CMS experimental analyses.

Enhanced accuracy in modeling top-associated boson production.

Abstract

We present theoretical predictions for the hadroproduction of t tbar W+, t tbar W- and t tbar Z at LHC as obtained by matching numerical computations at NLO accuracy in QCD with Shower Monte Carlo programs. The calculation is performed by PowHel, relying on the POWHEG-BOX framework, that allows for the matching between the fixed order computation, with input of matrix elements produced by the HELAC-NLO collection of event generators, and the Parton Shower evolution, followed by hadronization and hadron decays as described by PYTHIA and HERWIG. We focus on the dilepton and trilepton decay channels, studied recently by the CMS Collaboration.