Search of new physics with an Effective Field Theory model in pp→ZZjj, ZZjj→ℓℓvvjj events produced in ATLAS at LHC at √s=13.6 TeV

The standard model effective filed theory provides a theoretical framework that suggests potential new physics beyond the electroweak scale. In this framework, dimension-eight operators can be introduced to the effective Lagrangian, modifying vector boson scattering (VBS) cross sections via anomalous quartic gauge couplings (aQGCs). The dimension-eight operators’ contribution to the Lagrangian is quantified by the Wilson coefficient. In the following study only one non-zero Wilson coefficient is considered at a time. Limits of the aQGCs were derived using Run 2 data and Mote Carlo simulated data through pp → ZZjj, ZZjj → ℓℓννjj process in the ATLAS experiment at the Large Hadron Collider(LHC) at CERN. In order to minimize contributions of background processes to the signal cuts are applied in the DATA. To extract the limits a binned likelihood fit to the observable of interest was used. In the case the observables are the transverse mass of ZZ, the transverse momentum of Z, and the sum of momentum of all products. The tool to extract the limits is called EFTfun but in addition to that, a simple likelihood fit was developed. To test its accuracy pseudoexperiments were performed. Moreover, the effect of the systematic uncertainties to the fit was checked. Lastly, the impact of the aQGCs on the unitarity was studied, using the clipping technique meaning cutting off the contribution of the Wilson coefficient above certain energy called the clipping energy. Limits on the aQGCs were derived for various clipping energies.