The four scalar degrees of freedom of the Standard Model, the Higgs and the longitudinal components of the Ws and Z, are amenable to different effective field theory descriptions. "SMEFT" wraps them up in a single Higgs doublet, whereas "HEFT" treats the Higgs and the Goldstones separately. We seek to understand the suitability of "SMEFT" and "HEFT" for describing the effects of possible heavy new physics in, e.g., LHC measurements.
We identify physical features that can only be described by HEFT, and thereby identify two classes of beyond the Standard Model physics for which a HEFT description of their low energy physics is required: i) those which contain extra sources of electroweak symmetry breaking, ii) those which contain particles getting most of their mass from the Higgs mechanism. We show how some "HEFTy" theories are still viable given current experimental constraints.
High-Energy Resummation for Higgs-Plus-Jet(s) Production
Traditional theoretical uncertainties in collider predictions are improved by calculating to higher fixed-order accuracy; however, jet processes at the LHC are sensitive to logs in s-hat which damage the convergence of such an expansion. These are particularly enhanced by certain experimental cuts such as vector-boson-fusion cuts, vector-boson-scattering cuts or when searching for new physics at large m_jj. I’ll discuss the High Energy Jets framework which allows the calculation of new predictions which resum these logs and their impact in experimental analyses.