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

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 $ZZ\to \ell \ell \nu \nu$ 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 $WZ\to \ell \nu \ell \ell$ 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.

Comments: 11 pages, 5 figures, 4 tables. Submitted to Physics of Atomic Nuclei