Higher-order EW corrections in ZZ and ZZj production at the LHC

TL;DR

This paper advances the precision of theoretical predictions for ZZ and ZZj production at the LHC by calculating exact NLO EW corrections, comparing approximation methods, and integrating these into event simulations.

Contribution

It provides the first exact NLO EW results for pp→e+e−μ+μ−j and combines them with Sudakov resummation for improved accuracy, including implementation in the Sherpa event generator.

Findings

Exact NLO EW results for ZZj production are presented.

Comparison of EW virtual and Sudakov approximations shows their relative accuracy.

Inclusion of EW corrections in simulations improves the precision of LHC predictions.

Abstract

We consider the production of a pair of $Z$ bosons at the LHC and study the inclusion of EW corrections in theoretical predictions at fixed order and based on multijet-merged parton-shower simulations. To this end we present exact NLO EW results for $pp\to e^+e^-\mu^+\mu^-$, and, for the first time, for $pp\to e^+e^-\mu^+\mu^-j$, and compare them to the EW virtual and NLL Sudakov approximation. We then match the exact NLO EW result to the resummed Sudakov logarithms to achieve an improved NLO EW + NLL $\text{EW}_\text{sud}^\text{exp}$ result. Further, we discuss the inclusion of the above EW corrections in MEPS@NLO event simulations in the framework of the Sherpa event generator. We present detailed phenomenological predictions for inclusive $ZZ$ and $ZZj$ production taking into account the dominant EW corrections through the EW virtual approximation, as well as through (exponentiated) EW Sudakov logarithms.