Theory Seminar (High Energy/Cosmology) |
Events During the Week of April 12th through April 19th, 2026
Monday, April 13th, 2026
- Constructibility of Massive Helicity Amplitudes and the ALT Shift
- Time: 1:00 pm - 2:30 pm
- Place: Chamberlin 5280
- Speaker: Zhen Liu, Minnesota U.
- Abstract: Recursive constructions in amplitudes are a strong feature that requires careful analytic continuation with momentum shift to yield the full, correct, physical amplitudes. If not done systematically, an undetermined contact term would arise. We study the All-Line Transverse (ALT) shift, which we developed for on-shell recursion of amplitudes for particles of any mass. Our method allows for a nice and clean determination of the constructibility of the underlying theory. We apply the shift to the QED, electroweak theory, and higher-spin Compton scattering. The ALT shift framework allows consistent treatment in dealing with contact term ambiguities for renormalizable massive and massless theories, which we show can be useful in studying real-world amplitudes with massive spinors. Event recording:
- Host: Joshua Foster
Tuesday, April 14th, 2026
- No events scheduled
Wednesday, April 15th, 2026
- No events scheduled
Thursday, April 16th, 2026
- No events scheduled
Friday, April 17th, 2026
- No events scheduled