Off-shell single-top production at NLO matched to parton showers

TL;DR

This paper presents a next-to-leading order QCD simulation of off-shell single-top production with parton shower matching, including non-resonant effects, and compares it to on-shell results for LHC phenomenology.

Contribution

It introduces a method for simulating off-shell single-top production at NLO matched to parton showers, accounting for non-resonant and off-shell effects.

Findings

Accurate NLO+PS simulations of off-shell single-top production.

Comparison showing differences between off-shell and on-shell results.

A general approach applicable to resonant processes with parton showers.

Abstract

We study the hadroproduction of a $Wb$ pair in association with a light jet, focusing on the dominant $t$-channel contribution and including exactly at the matrix-element level all non-resonant and off-shell effects induced by the finite top-quark width. Our simulations are accurate to the next-to-leading order in QCD, and are matched to the HERWIG6 and PYTHIA8 parton showers through the MC@NLO method. We present phenomenological results relevant to the 8 TeV LHC, and carry out a thorough comparison to the case of on-shell $t$-channel single-top production. We formulate our approach so that it can be applied to the general case of matrix elements that feature coloured intermediate resonances and are matched to parton showers.