The origin of flavour: from the Higgs boson to rare pion decays


The elementary fermions we discovered so far are arranged in three flavours in the Standard Model of Particle Physics (SM). While the model has been extremely successful at describing properties like their mass hierarchies and mixings through this flavour structure, it fails short at explaining them. In this talk, I will present two avenues where measurements of SM quantities can point us toward a theory of flavour. The first one employs the ATLAS experiment at the LHC where the tau lepton — the heaviest cousin of the electron— offers the opportunity to study the Yukawa interaction responsible for the mass hierarchy of the fermions. The second avenue makes use of rare pion decays, a pristine probe of lepton flavour universality and quark mixing. PIONEER, a next-generation experiment proposed at the Paul Scherrer Institute, is set to improve the precision of rare pion decays ten-fold over current experiments. I will give an overview of the project and present the challenges and promises of the detector design.

Recording (requires NetID)

Speaker : 

Quentin Buat, UW


CENPA Conference Room NPL-178, Zoom link: