Searching for the Higgsino-Bino sector at the LHC

Abstract

We study the search for electroweakinos at the 13 TeV LHC in the case of heavy scalar superpartners. We consider both the direct production mode and the one associated with the decay of heavy Higgs bosons, and concentrate on the case of light Higgsinos and Binos. In this case, the direct production searches becomes more challenging than in the light Wino scenario. In the direct production mode, we use the current experimental searches to set the reach for these particles at larger luminosities, and we emphasize the relevance of considering both the neutral gauge boson and the neutral Higgs decay modes of the second and third lightest neutralino. We show the complementarity of these searches with the ones induced by the decay of the heavy Higgs bosons, which are dominated by the associated production of the lightest neutralino with the second and third lightest ones, with the latter decaying into gauge bosons. We show that, depending on the value of tan β, the Higgs boson decay channel remains competitive with the direct production channel up to heavy Higgs boson masses of about 1 TeV. Moreover, this search is not limited by the same kinematic considerations as the ones in the direct production mode and can cover masses up to the kinematic threshold for the decay of the heavier electroweakinos into the lightest neutralino. This decay mode provides also an alternative way of looking for heavy Higgs bosons in this range of masses and hence should be a high priority for future LHC analyses.

HL-LHC and ILC sensitivities in the hunt for heavy Higgs bosons

“…2 caused by a transition of the most sensitive production channel from gluon fusion (at low tan β values) to bottom quark associated production (at high tan β values). At tan β = 20 the reach in the M 125 h (χ) scenario is significantly reduced to M A 1700 GeV compared to the M 125 h scenario with M A 2000 GeV. On the other hand, at large values of tan β ∼ 50 and thus large M A the reach is only slightly weaker than in the M 125 h scenario, as for those M A values in both scenarios decays into electroweakinos are kinematically open.…”

“…In this paper we present the HL-LHC and ILC 1 sensitivities to heavy Higgs bosons in the M 125 h scenario [10], in which all supersymmetric particles are heavy, leaving essentially a Two-Higgs-Doublet Model (THDM)-like Higgs sector at the electroweak scale, and the M 125 h (χ) scenario [10], which features light neutralinos and charginos. For the low tan β region we furthermore study the analogous scenarios M 125 h,EFT and M 125 h,EFT (χ), respectively, which employ a dedicated effective field theory (EFT) calculation and a varying SUSY mass scale [11]. In addition, we define in this work a new benchmark scenario in which the decays of the Higgs bosons to pairs of bottom quarks are enhanced.…”

“…For larger values of M A decays into electroweakinos (EWinos) are kinematically open. In contrast, the M 125 h (χ) scenario [10] features light EWinos via the choice of relatively small values of the bino, wino and Higgsino mass parameters, M 1 , M 2 and μ, respectively. This leads to sizable decay rates of the heavy Higgs bosons H and A into charginos and neutralinos throughout the parameter plane, thus diminishing the event yield of the τ + τ − and bb final state signatures that are used to search for the additional Higgs bosons at the LHC.…”

“…Accordingly, for these scenarios we employ the THDM as effective field theory (EFT) below the SUSY scale to calculate the higher-order corrections to the Higgs-boson masses and self-energies [36]. The M 125 h,EFT scenario resembles the M 125 h scenario, while the M 125 h,EFT (χ) scenario is phenomenologically similar to the M 125 h (χ) scenario, i.e. it features light electroweakinos.…”

“…This, in turn, changes the relative sensitivity of heavy Higgs boson searches in bb and τ + τ − final states. In order to investigate this change in sensitivity we define one new benchmark scenario, which we denote by M 125 h (μ = −2 TeV) or the short-hand notation M 125,μ− h . 3 The SUSY input parameters are chosen to be…”