Approximate alignment in two-Higgs-doublet model with extra Yukawa couplings

Abstract

With discovery of the 125 GeV boson h 0 , the existence of a second doublet is very plausible. We show that the "alignment" phenomenon, that h 0 is found to resemble closely the Standard Model Higgs boson, may correspond to Higgs quartic couplings ηi that are O(1) in strength. If the exotic bosons of the second doublet possess extra top Yukawa couplings, which are the least constrained by data, such a two Higgs doublet model could drive electroweak baryogenesis, as well as further "protect" the apparent alignment. The exotic Higgs bosons can be sub-TeV in mass while remaining well hidden so far, with broad parameter space for search at the Large Hadron Collider.

Implications of four-top and top-pair studies on triple-top production

“…If such is the case, one could maintain custodial SU(2), i.e. near degeneracy of A-H + that are heavier than H, which would have larger allowed parameter range [11] than the case of twisted custodial symmetry that we have illustrated above. One should not only consider two states, i.e.…”

“…where c γ ≡ cos γ and s γ ≡ sin γ describe mixing between the two CP -even scalars (c γ → 0 is the alignment limit; see Ref. [11] As discussed earlier, the cg → tH/tA → ttt processes are induced by ρ tc and ρ tt couplings. However, non-zero ρ tt and ρ tc induce gg → H/A → tt and gg → H/A → tc, as well as cg → tH/A → ttc processes at LHC.…”

“…We consider g2HDM with CP -conserving Higgs sector. The CP -even scalars h, H and the CP -odd scalar A couple to fermions by [11,15]…”

Probing an additional bottom Yukawa coupling via bg→bA→bZH signature

“…A larger ρ tt would alleviate the significances further if m A /m H > 2m t . Besides, ρ τ τ is likely O(λ τ ) [7], although, the impact is negligibly small for both the processes in all three BPs. Here, we assumed the flavor changing neutral Higgs coupling ρ tc to be small, however, a O(1) value is still allowed by the current data [64,65] (see also Ref.…”

Cancellation mechanism for the electron electric dipole moment connected with the baryon asymmetry of the Universe

“…g2HDM, EWBG, and ThO EDM.-The g2HDM extends SM by adding one extra Higgs doublet [5], but without imposing a Z 2 symmetry. With concerns of flavor changing neutral Higgs (FCNH) couplings controlled by [6] fermion mass and mixing hierarchies plus alignment (i.e. close proximity of h(125) to SM Higgs boson), the phenomenological consequences of g2HDM is much richer than usual 2HDMs with Z 2 symmetries [5].…”