Title: ‘EFTs for BSM: Counting, Ambiguities, and Application’

Speaker: Shakeel Ur Rahaman (IPPP Durham).

Venue&Time: Red Room / 15:00

Abstract: The two principal frameworks for modeling the Beyond Standard Model physics as an Effective Field Theory (EFT) are the Standard Model EFT (SMEFT) and the Higgs Effective Field Theory (HEFT). SMEFT is constructed in the electroweak symmetric phase, inherently utilizing the Higgs doublet, whereas HEFT is defined in the broken phase using the physical Higgs boson alongside a separate set of Goldstone bosons. The unavoidable necessity of truncating these effective field theory expansions creates technical ambiguities that are fundamentally interwoven with the redundancies inherent in general field redefinitions. In this talk regarding HEFT, the focus will be primarily on its methodology for building operators, its power counting scheme, and the associated truncation uncertainties. These properties are already well-established within the SMEFT framework. For SMEFT, the discussion will center on its application in precision calculations and its practical implementation in Monte Carlo event generators such as Sherpa.