Speaker
Description
We discuss various aspects of (multi-) Higgs boson production from longitudinal electroweak gauge bosons $W_L W_L \to n \times h$ in the TeV region as the necessary information to characterise the Flare function, $\mathcal{F}(h)$, which determines whether the Standard Model EFT (SMEFT) or the Higgs EFT (HEFT -also sometimes referred as the EW Chiral Lagrangian-) is the appropriate description. We show a set of new correlations among BSM corrections to the HEFT coefficients that help decide, from experimental data, whether we have a viable SMEFT low-energy scenario. We present an effective field theory study of $W_L W_L$ scattering into two, three and four Higgs bosons in the final state. We consider the general HEFT approach and then particularize it for SMEFT scenarios. We make use of the equivalence theorem and improve previous results on $W_L W_L \to n \times h$ cross sections, showing several important cancellations and simplifications which allows us to display these amplitudes in a very compact form. We show that for a growing number of Higgs bosons in the final state, SMEFT leads to an important suppression of the cross sections with a large number of Higgses, while this does not happen for general HEFT low-energy scenarios (which do not accept a SMEFT description). We provide some numerical estimates of these multi-Higgs cross sections based on current experimental bounds.
