Abstract

Measurements of the invisible decay width of the Z boson represent precision tests of the electroweak sector of the Standard Model (SM). This seminar will focus on recent results of this decay width from the ATLAS and CMS experiments at the Large Hadron Collider and compare them with legacy measurements from the Large Electron-Positron Collider. In this seminar we will review the methodologies employed by ATLAS and CMS to extract the Z invisible width, highlighting differences in experimental techniques, detector capabilities, and statistical precision. As deviations from the SM prediction can be indications of physics beyond the SM, such as additional neutrino species or exotic decay modes, we will highlight any tensions or agreement within uncertainties between the various measurements.

Speakers

Giulia Sorrentino obtained her PhD from the University of Trieste in 2023, with a thesis focused on the analysis of the Z boson decay into two neutrinos and a photon. Currently a postdoctoral researcher at Kansas State University, she is a member of the CMS collaboration, working on measurements in the Higgs sector and contributing to the development of a new time-of-flight detector for the high-luminosity phase of the LHC.

Martin Klassen is an experimental physicist at the ATLAS experiment and currently a postdoctoral researcher at Tufts University, having completed his PhD at Heidelberg University in 2023. His research interest centers on Standard Model precision measurements, cross section measurements of Z and W boson production in association with jets, as well as dark matter searches.