Analysis of the W-Boson Mass anomaly with a 4-fermion operator

Details

Supervisors

Degrande, Céline

Faculty

Faculté des sciences

Degree label

Master [120] en sciences physiques, à finalité approfondie

Abstract

It is well known by the scientific community that the standard model is not complete. In collider physics, it is commonly assumed that new physics takes place at higher energy. In this case, one uses effective field theories to model the effect of high energy physics at smallest scales. Recently, CDF II collaboration published in Science Magazine a high precision measurement of the W boson mass that appeared to be in tension with the standard model prediction. The main idea of the fitting method is simulating distributions for different masses of the W boson and comparing them to the experimental ones. In this work, we analyzed the effect of a four fermion operator on these distributions. We have generated events with Monte Carlo generator MadGraph5_aMC@NLO and have computed distributions for different values of the new physics contribution. We have investigated whether or not the new physics contribution can deceive a mass fit. If yes, we estimated the new physics contribution should be needed to find the mass shift observed by the CDF II collaboration. We have finally investigated the effect of this new physics on the parameters in the standard model related to the W boson.