Fixed-order and merged parton-shower predictions for WW and WWj production at the LHC including NLO QCD and EW corrections

TL;DR

This paper combines NLO QCD and electroweak corrections for WW and WW+jets production at the LHC, providing merged parton-shower predictions that improve stability and accuracy over fixed-order calculations.

Contribution

It introduces a comprehensive analysis including both fixed-order and all-order merged predictions with electroweak effects for WW processes at the LHC.

Findings

Merged predictions are more stable than fixed-order calculations.

Higher-order effects significantly impact cross sections and distributions.

Merged simulations improve agreement with experimental setups.

Abstract

First, we present a combined analysis of ${\rm p}{\rm p} \to \mu^+ \nu_\mu {\rm e}^- \bar \nu_{\rm e}$ and ${\rm p}{\rm p} \to \mu^+ \nu_\mu {\rm e}^- \bar \nu_{\rm e} {\rm j}$ at next-to-leading order, including both QCD and electroweak corrections. Second, we provide all-order predictions for ${\rm p}{\rm p} \to \mu^+ \nu_\mu {\rm e}^- \bar \nu_{\rm p}+\mathrm{jets}$ using merged parton-shower simulations that also include approximate EW effects. A fully inclusive sample for WW production is compared to the fixed-order computations for exclusive zero- and one-jet selections. The various higher-order effects are studied in detail at the level of cross sections and differential distributions for realistic experimental set-ups. Our study confirms that merged predictions are significantly more stable than the fixed-order ones in particular regarding ratios between the two processes.