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High Energy Physics Seminar

Monday, October 17, 2022
4:00pm to 5:00pm
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Online and In-Person Event
Gauge Invariance from On-Shell Massive Amplitudes and Tree-level Unitarity
Da Liu, UC Davis,

In this talk, I will discuss about my recent work about the on-shell understanding of the spontaneously broken gauge theories by employing the on-shell massive spinor formalism and tree unitarity. We start from the most general on-shell three-particle amplitudes with energy growing behavior at most of O(E) involving arbitrary, finite number of massive scalars, spinors and vectors. Then the factorizable parts of the four-particle amplitudes are calculated by gluing the on-shell three-particle amplitudes together and utilizing the fact that tree-level amplitudes have only simple poles. The contact parts of the four-particle amplitudes are further determined by tree unitarity, which also puts strong constraints on the possible allowed three-particle coupling constants and the masses. The derived relations among them converge to the predictions of gauge invariance in the UV theory, which is consistent with the classic results by Cornwall, Levin and Tiktopoulos.

In person attendees (469 Lauritsen) must have a valid Caltech ID.

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