h → Zγ in the complex two Higgs doublet model

Abstract

Abstract:The latest LHC data confirmed the existence of a Higgs-like particle and made interesting measurements on its decays into γγ, ZZ * , W W * , τ + τ − , and bb. It is expected that a decay into Zγ might be measured at the next LHC round, for which there already exists an upper bound. The Higgs-like particle could be a mixture of scalar with a relatively large component of pseudoscalar. We compute the decay of such a mixed state into Zγ, and we study its properties in the context of the complex two Higgs doublet model, analysing the effect of the current measurements on the four versions of this model. We show that a measurement of the h → Zγ rate at a level consistent with the SM can be used to place interesting constraints on the pseudoscalar component. We also comment on the issue of a wrong sign Yukawa coupling for the bottom in Type II models.

Large pseudoscalar Yukawa couplings in the complex 2HDM

“…In order to understand how the model will perform at the end of the next LHC run we use the expected precisions on the signal strengths of different Higgs decay modes by the ATLAS [15,16] and CMS [17] collaborations (see also [18]) for √ s = 14 TeV and for 300 and 3000 f b −1 of integrated luminosities. As previously shown in [9], the final states V V , γγ and τ + τ − are enough to reproduce quantitatively the effect of all possible final states in the Higgs decay. Therefore, taking into account the predicted precision for the signal strength, we will consider the situations where, at 13 TeV, the rates are measured within either 10% or 5% of the SM prediction.…”

“…As previously discussed we JHEP06(2015)060 will consider the rates for the processes µ V V , µ γγ and µ τ τ to be within 20% of the expected SM value, which at present roughly matches the average precision at 1σ. It was shown in [9] that taking into account other processes with the present attained precision has no significant impact in the results. We start by examining the parameter space for a center of mass energy of √ s = 8 TeV corresponding to the end of the first LHC run.…”

“…Therefore, taking into account the predicted precision for the signal strength, we will consider the situations where, at 13 TeV, the rates are measured within either 10% or 5% of the SM prediction. We should note that no difference can be seen in the plots when the energy is changed from 13 to 14 TeV as discussed in [9]. This paper is organized as follows.…”

“…The complex 2HDM was recently reviewed in great detail in [9] (see also [6,[19][20][21][22][23][24]). Therefore, in this section we will just briefly describe the main features of the complex two two-Higgs doublet with a softly broken Z 2 symmetry φ 1 → φ 1 , φ 2 → −φ 2 whose scalar potential we write as [5] V H = m 2 11 |φ 1 | 2 + m 2 22 |φ 2 | 2 − m 2 12 φ † 1 φ 2 − (m 2 12 ) * φ † 2 φ 1…”

“…The gluon fusion cross section is calculated at NNLO using HIGLU [56] together with the corresponding expressions for the CP-violating model in [9]. SusHi [57] at NNLO is used for calculating bb → h, while V h (associated production), tth and V V → h (vector boson fusion) can be found in [58].…”