TH BSM Forum

The electroweak effective field theory from on-shell amplitudes

by Gauthier Durieux (Technion)

4/2-037 - TH meeting room (CERN)

4/2-037 - TH meeting room


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On-shell methods trivialize the representation of particles to provide an efficient description of scatterings without gauge or field redefinition redundancies. Applications to effective field theories (EFTs) led to new understandings (e.g. of non-renormalizations and non-interferences) and simpler descriptions (e.g. for operator enumerations). We applied the massive spinors formalism of Arkani-Hamed, Huang and Huang to the electroweak sector of the standard-model EFT. All massive three-point amplitudes were systematically bootstrapped assuming only Poincaré symmetry, locality, and the relevant particle spectrum. The electroweak symmetry was explicitly observed to emerge from perturbative unitarity, offering a purely bottom-up perspective on the Higgs mechanism. A full example of four-point amplitude was worked out, including both factorizable and contact terms. The matching between amplitude and operator coefficients was finally performed and paves the way for electroweak-EFT computations with on-shell methods.