Composite effective field theory signal in case of searching for neutral triple gauge couplings with $ZZ\rightarrow\ell\ell\nu\nu$ production

TL;DR

This paper introduces a composite effective field theory method to improve sensitivity in searching for neutral triple gauge couplings in ZZ production, significantly tightening limits on Wilson coefficients by accounting for background effects.

Contribution

It presents a novel composite anomalous signal method that enhances sensitivity to EFT operators by considering their impact on backgrounds, applied to ZZ to 2l2nu production.

Findings

Background contributions from WZ are significant for BSM signals.

Limits on Wilson coefficients improved by up to 94.4%.

Method enhances sensitivity independently of luminosity growth.

Abstract

In this work manifestations of physics beyond the Standard Model are parameterized with higher-dimension operators and Wilson coefficients using effective field theory. In order to set more stringent experimental limits on the Wilson coefficients it is crucial to use new methods of sensitivity increasing that work independently with luminosity growth. Method of composite anomalous signal allows one to set the limits on Wilson coefficients more precisely and stringent by accounting for impact of EFT operators on background processes in addition to the conventional anomalous contribution from the signal process. This work presents aforementioned methodology applied to the $ZZ\rightarrow\ell\ell\nu\nu$ production, that is sensitive to the neutral triple couplings of gauge bosons $Z$ and $\gamma$. It is found that the main background BSM contribution comes from $WZ\rightarrow\ell\nu\ell\ell$ background. Improvement of the limits on the Wilson coefficients due to this background depends on the coefficient and is up to 57.5% (59.1%) for one- (two-) dimensional limits in linear + quadratic effective field theory model and up to 94.4% for one-dimensional limits in linear effective field theory model.