The MSSM Higgs sector at a high MSUSY: reopening the low tan β regime and heavy Higgs searches

Abstract

One of the main implications of the LHC discovery of a Higgs boson with a mass M h ≈ 126 GeV is that the scale of supersymmetry-breaking in the Minimal Supersymmetric Standard Model (MSSM) might be rather high, M S ≫ M Z . In this paper, we consider the high M S regime and study the spectrum of the extended Higgs sector of the MSSM, including the LHC constraints on the mass and the rates of the observed light h state. In particular, we show that in a simplified model that approximates the important radiative corrections, the unknown scale M S (and some other leading SUSY parameters) can be traded against the measured value of M h . One would be then essentially left with only two free parameters to describe the Higgs sector, tan β and the pseudoscalar Higgs mass M A , even at higher orders. The main phenomenological consequence of these high M S values is to reopen the low tan β region, tan β < ∼ 3-5, which was for a long time buried under the LEP constraint on the lightest h mass when a low SUSY scale was assumed. We show that, in this case, the heavier MSSM neutral H/A and charged H ± states can be searched for in a variety of interesting final states such as decays into gauge and lighter Higgs bosons (in pairs on in mixed states) and decays into heavy top quarks. Examples of sensitivity on the [tan β, M A ] parameter space at the LHC in these channels are given.

Doubling up on supersymmetry in the Higgs sector

“…Other radiative corrections to the Higgs mass matrix have been studied in [42][43][44][45][46]. Direct analysis of the dominant one-loop contributions from top-stop loops shows that -6 -…”

“…This is shown in figure 6 as a grey excluded region excluding a range of m A for tan β 7. We do not display the constraint from H ± → τ ± ν searches, which exclude a small region at small m A and large tan β that is contained within the grey area [42][43][44][45].…”

“…Results of such an analysis [47,48] indicate that, even in such heavy-M SU SY scenarios, the predictions of the hMSSM agree within a few percent with the exact results for m H , α and λ Hhh , as long as the condition µX t /M 2 SU SY 1 is satisfied. For the purposes of our N = 2 study here, which is restricted to the Higgs sector, we follow the philosophy proposed in [42][43][44][45][46], in which the hMSSM scenario was introduced to discuss the N = 1 MSSM Higgs sector. The idea is again to use the known output m h instead of the unknown input , adjusting so as to obtain m h = 125 GeV.…”

Interference effects in the decays of spin-zero resonances into γγ and t t ¯ $$ t\overline{t} $$

“…Hence, the only relevant decays at low tan β values are those into tt pairs, whereas the modes Φ → bb, τ + τ − are relevant only at high tan β. All other decay modes, including those to vector boson pairs or to the lighter Higgs and a gauge boson, are strongly suppressed in the alignment/decoupling limits of 2HDMs such as the MSSM [47][48][49]. In addition, for the mass range M A ≈ M H ≈ M H ± assumed in our analysis, the decays H/A → A/H + Z or H ± W ∓ are kinematically forbidden at the two-body level and, hence, strongly suppressed.…”

“…As specific models, we consider first minimal scenarios in which the Φ is either a single scalar H or a pseudoscalar A, as was discussed in [5,6], with the broad and narrow total decay widths given above. We then consider a non-minimal scenario with a pair of near-degenerate states H and A, with the couplings and mass difference M H − M A = 16 GeV found in a supersymmetric version of the Type-II 2HDM with tan β = 1 [47][48][49]. [72].)…”