Abstract
We consider extended scalar sectors of the Standard Model as ultraviolet complete motivations for studying the effective Higgs self-interaction operators of the Standard Model effective field theory. We investigate all motivated heavy scalar models which generate the dimension-six effective operator, |H|6, at tree level and proceed to identify the full set of tree-level dimension-six operators by integrating out the heavy scalars. Of seven models which generate |H|6 at tree level only two, quadruplets of hypercharge Y = 3YH and Y = YH, generate only this operator. Next we perform global fits to constrain relevant Wilson coefficients from the LHC single Higgs measurements as well as the electroweak oblique parameters S and T. We find that the T parameter puts very strong constraints on the Wilson coefficient of the |H|6 operator in the triplet and quadruplet models, while the singlet and doublet models could still have Higgs self-couplings which deviate significantly from the standard model prediction. To determine the extent to which the |H|6 operator could be constrained, we study the di-Higgs signatures at the future 100 TeV collider and explore future sensitivity of this operator. Projected onto the Higgs potential parameters of the extended scalar sectors, with 30 ab−1 luminosity data we will be able to explore the Higgs potential parameters in all seven models.
Highlights
The Higgs self-coupling directly determines the shape of the Higgs potential and measuring possible deviations of the Higgs self-coupling from its SM value is a crucial step in understanding the nature of EWSB, electroweak vacuum stability, and the nature of the electroweak phase transition (EWPT)
5Though in 2HDM the modification of the Wilson coefficient ctH can be large enough to modify the di-Higgs production cross section to give some evidence in 14 TeV LHC, yet other models we considered definitely need the help of 100 TeV collider to probe, due to small or zero ctH
We show the significance of the model parameter λΦ3H vs new physics scale M varies with the 30 ab−1 in contours, while the blue region is excluded by the constraint on cHD from Electroweak precision data (EWPD)
Summary
We consider all ultraviolet (UV) complete models which include one additional heavy scalar which generate, after integrating out the new scalar, dimension-six operators affecting the trihiggs vertex at tree level. In order to generate tree level dimension-six operators one needs a term H2S or H3S, where S is the new heavy scalar, this is a result of all other models having an additional Z2 symmetry due to the requirements of the gauge symmetry and renormalizability.. For each model we write down the Lagrangians for each UV-model along with the corresponding effective field theory (EFT) to dimension-six at tree level, we will only write the new terms in addition to the standard model terms for convenience. To clarify our notation and conventions, we write here the general Lagrangian for all UV complete models, neglecting SM fermionic and gauge boson terms, considered:. We will employ particular choices of the fermionic matrices in the model to suppress off diagonal components, as is motivated by studies of flavor changing neutral currents, and assume these operators to be diagonal
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