A positive-weight next-to-leading order simulation of weak boson pair production

TL;DR

This paper presents a simulation method for weak boson pair production using positive-weight NLO matching in Herwig++, incorporating full showering effects, spin correlations, and extensive validation against other approaches.

Contribution

It introduces a positive-weight NLO simulation for diboson production in Herwig++, including full showering and spin effects, with thorough validation.

Findings

Accurate modeling of diboson production with positive-weight NLO matching.

Inclusion of full showering effects and spin correlations.

Validated against alternative methods, demonstrating reliability.

Abstract

In this article we describe simulations of ZZ, WZ and WW production based on the positive weight next-to-leading-order matching scheme, Powheg, in the Herwig++ event generator. Building on earlier efforts within the Herwig++ framework, the simulation includes a full description of truncated showering effects, required to correctly model soft, wide angle, emissions in angular-ordered parton showers. We utilize simple relations among each of the diboson cross sections, holding to order alpha_S, in constructing the simulation. Spin correlation effects are also included in the decays of the vector bosons at the tree order. A large part of this work is concerned with a full and thorough validation of the simulations through comparisons with alternative methods and calculations.