Heavy Higgs searches: flavour matters

Abstract

We point out that the stringent lower bounds on the masses of additional electrically neutral and charged Higgs bosons crucially depend on the flavour structure of their Yukawa interactions. We show that these bounds can easily be evaded by the introduction of flavour-changing neutral currents in the Higgs sector. As an illustration, we study the phenomenology of a two Higgs doublet model with a Yukawa texture singling out the third family of quarks and leptons. We combine constraints from low-energy flavour physics measurements, LHC measurements of the 125 GeV Higgs boson rates, and LHC searches for new heavy Higgs bosons. We propose novel LHC searches that could be performed in the coming years to unravel the existence of these new Higgs bosons.

$$ {R}_{D^{\left(*\right)}},{R}_{K^{\left(*\right)}} $$ and neutrino mass in the 2HDM-III with right-handed neutrinos

“…Following the discussions made explicitly in refs. [46,85,144], which are sufficient for the current purpose, we have found that all these experimental bounds can be satisfied by the parameter regions allowed by the R D ( * ) and R K ( * ) anomalies. As a further nonzero ct needs to be introduced to X u 1 in order to provide a resolution to the muon g − 2 excess while complying with the tight constraints from the B-physics observables [136], we plan to perform a detailed study of the direct LHC constraints on the charged and neutral scalars at nonzero values of tt , tc and ct , as well as the neutrino Yukawa couplings in an upcoming paper.…”

Large h→bs in generic two-Higgs-doublet models

“…For a recent discussion of flavour violation involving the top quark see Ref. [86]. Finally, H, A → γγ in our model is particularly interesting in light of the CMS excess at 95 GeV.…”

Rare top decays as probes of flavorful Higgs bosons

“…In our flavorful 2HDMs, 50% of the time the final state will be same-sign tops, in contrast to 2HDMs with natural flavor conservation that only produce opposite sign tops. Same-sign tops have been identified as important probes in a number of new physics scenarios, including RPV SUSY [56], 2HDMs [35,57,58], additional scalars [59,60], colored vectors [61], and effective field theories [62]. The cross section of same-sign tops in our scenario is shown in the left plot of In [55] searches for same-sign leptons are interpreted in a benchmark model in which same-sign tops are created by a neutral spin-1 mediator.…”

“…2HDMs with a right-handed top that is singled out by a symmetry have been discussed e.g. in [28,35]. Here we follow the second option and set the U (1) charges Q Φ = −Q Q 3 = +1, while leaving the right-handed top uncharged.…”

“…The Yukawa structure of the F2HDM can be for example generated via the flavor-locking mechanism [23,24], and the implied collider phenomenology has been discussed in detail in [25]. Variations of the original F2HDM with alternative flavor structures were explored in [26] (for additional recent work on extended Higgs sectors with non-standard flavor structures see [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]).…”