Abstract: A key parameter that characterizes the Higgs boson is its decay width. Accurate measurements of this quantity could provide insights into the Higgs boson’s couplings to particles both within and beyond the Standard Model (SM). However, the SM predicts an extremely narrow Higgs width, far below what can be measured directly, making precise experimental determination highly challenging. In this talk, we will review two theoretical proposals that enable indirect bounds on the width: the off-shell and on-shell methods. We will explore how ATLAS probes the Higgs width using both approaches, emphasizing the significance of these studies in detecting potential deviations from the SM. Additionally, we will cover the current limitations in the measurements, such as uncertainties arising from missing higher-order corrections and the sub-optimality of the analysis techniques that limit the precision of ATLAS’s results. We aim to provide a comprehensive review of the current status of theoretical predictions and experimental measurements, the challenges involved, and future prospects for constraining or discovering new physics through Higgs width studies.
About the speakers:
Federico Buccioni is a Postdoctoral researcher at the Technical University of Munich (TUM). He obtained his PhD from the University of Zurich and after that he moved to Oxford University for his first Postdoc. After Oxford he joined TUM on a 5-years position. His research interests revolve around precision collider phenomenology within the Standard Model, in particular higher-order corrections to precision observables. As far as LHC pheno is concerned, he has worked on higher-order corrections to the Drell-Yan process, studies of background processes to associated ttH production and more recently interference effects in Higgs-mediated Z-gamma and gamma-gamma production. The latter effects have the potential to constrain the Higgs-boson width at hadron colliders.
Jay Sandesara is a Ph.D. student at the University of Massachusetts Amherst working with the ATLAS collaboration at CERN. He contributed to the latest ATLAS Run-2 measurement of off-shell Higgs boson production, which set stringent limits on the Higgs boson width. His current research focuses on developing a novel and highly optimized analysis technique to achieve the most precise measurement to date of the Higgs boson width using ATLAS experiment data, producing a legacy result as well as establishing a novel analysis framework for use in LHC experiments.