Speaker
Description
Among the open questions of particle physics is the origin of neutrino masses. These masses can be explained by the "Seesaw mechanism," which introduces Majorana neutrinos with masses on the TeV scale. This talk presents a search for such Majorana neutrinos produced in same-sign $WW$ scattering. The analysis uses 140 fb$^-1$ of $pp$ collison data collected between 2015 and 2018 by the ATLAS detector at the Large Hadron Collider. The analysis targets final states with with exactly two same-sign muons and at least two hadronic jets with a large separation in rapidity. The main backgrounds are the Standard Model same-sign $WW$ scattering and $WZ$ production. No significant excess over the Standard Model expectation is observed. The measurement results are interpreted in the phenomenological Type I Seesaw model and the Weinberg operator model.
