CMSA Quantum Matter/Quantum Field Theory Seminar: Global anomalies in the Standard Model(s) and Beyond


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April 22, 2020 10:30 am - 12:00 pm
via Zoom Video Conferencing

Joseph Davighi - DAMTP, University of Cambridge

Global anomalies in gauge theories are detected by the exponentiated eta-invariant, which becomes a cobordism invariant when perturbative anomalies vanish. We analyse global anomalies in four distinct (but equally valid) versions of the Standard Model of particle physics by computing the appropriate cobordism groups. In two cases we find that there are no global anomalies beyond the Witten anomaly associated with the SU(2) factor, while in the other cases we show that there are no global anomalies at all. This uncovers a subtle interplay between local and global anomalies in closely related gauge theories. We will then discuss a more subtle version of this `anomaly interplay' occurring in a U(2) gauge theory defined without a spin structure.

via Zoom Video Conferencing: