Thursday, May 2, 2024, 16:00
OSGA/EG06
Mikhail Gorshteyn, Mainz University
Abstract:
Unitarity of the Cabibbo-Kobayashi-Maskawa quark mixing matrix is a
mathematical expression of universality of the weak interaction across
lepton and quark sectors, as well as the Standard Model's completeness.
The most precisely measured top-row elements warrant Standard Model
tests at the 0.01% level. At this precision, the contribution of
Vub is negligible, leaving one with the simple Cabibbo
unitarity pattern, |Vud|=cosθC,
|Vus|=sinθC. Combining kaon decays with
nuclear beta decays, currently a 2.5σ deficit is observed. This
deficit, also coined the Cabibbo angle anomaly, relies on a body of
high-precision experimental measurements and theoretical calculations. I
give an overview of the recent developments in the SM theory of beta
decays of free and bound neutrons, and kaons. I discuss future steps, as
well as possible implications for BSM searches at low energies.