Electroweak Precision Physics from Beta Decays to the Z Pole

02.430 (Mainz Institute for Theoretical Physics, Johannes Gutenberg University)


Mainz Institute for Theoretical Physics, Johannes Gutenberg University

Staudingerweg 9 / 2nd floor, 55128 Mainz

Electroweak precision observables are excellent tests of the Standard Model of particle physics. Since the electroweak sector only depends on a few fundamental parameters, which can be measured in many different processes, it is significantly overconstrained. The corresponding consistency check is typically set up in terms of global fits. Traditionally focused on Z-pole observables, electroweak fits displayed some mild tensions, but have in general been consistent with the Standard Model. Recently, evidence for a deficit in the first-row unitarity of the CKM matrix has emerged, originating from combining Vud and Vus extractions from beta and kaon decays, respectively. Besides direct new-physics contributions, this observation could be interpreted as a modification of the Fermi constant extracted from muon decay. If explained in terms of modified W couplings, this also affects, via SU(2) invariance, those of the Z boson. Therefore, the global electroweak fit and the determination of the CKM elements become intertwined. In this workshop, we plan to explore this interplay, including prospects for improved Standard-Model predictions, experimental opportunities, and implications for new-physics scenarios. 

Contact MITP Team: Dominika Kosler