Invisible decays of the lightest Higgs boson in supersymmetric models

Abstract

We consider supersymmetric models in which the lightest Higgs scalar can decay invisibly consistent with the constraints on the 126 GeV state discovered at the CERN LHC. We consider the invisible decay in the minimal supersymmetric standard model (MSSM), as well its extension containing an additional chiral singlet superfield, the so-called next-to-minimal or nonminimal supersymmetric standard model (NMSSM). We consider the case of MSSM with both universal as well as nonuniversal gaugino masses at the grand unified scale, and find that only an E6 grand unified model with unnaturally large representation can give rise to sufficiently light neutralinos which can possibly lead to the invisible decay h 0 →χ 0 1χ 0 1 . Following this, we consider the case of NMSSM in detail, where also we find that it is not possible to have the invisible decay of the lightest Higgs scalar with universal gaugino masses at the grand unified scale. We delineate the regions of the NMSSM parameter space where it is possible to have the lightest Higgs boson to have a mass of about 126 GeV, and then concentrate on the region where this Higgs can decay into light neutralinos, with the soft gaugino masses M1 and M2 as two independent parameters, unconstrained by grand unification. We also consider, simultaneously, the other important invisible Higgs decay channel in the NMSSM, namely the decay into the lightest CP odd scalars, h1 → a1a1, which is studied in detail. With the invisible Higgs branching ratio being constrained by the present LHC results, we find that µ ef f < 170 GeV and M1 < 80 GeV is disfavored in NMSSM for fixed values of the other input parameters. The dependence of our results on the parameters of NMSSM is discussed in detail.

Invisible decays of the heavier Higgs boson in the minimal supersymmetric standard model

“…Although specific regions of the MSSM parameter space have been ruled out by these experiments, there is still a large portion of the MSSM parameter space which remains unexplored. Recently, the question of the invisible decays of the lightest Higgs boson in the context of the MSSM and the NMSSM have been discussed in detail [18,25]. In this paper we carry this investigation further by analyzing the decay patterns and the invisible decays of the heavier Higgs boson (H 0 ) of the MSSM.…”

“…If one is interested in Higgs boson decaying invisibly into light neutralinos, it is appropriate to consider a light or massless eigenstate of the mass matrix (III.1). It has been shown earlier [18,25] that with the gaugino mass parameters satisfying the universal boundary conditions at the GUT scale, it is not possible to satisfy the masslessness condition for the lightest neutralino following from the determinant of the mass matrix (III.1) and the experimental constraints as implied by the LEP experiments [43]. Thus, a massless neutralino is ruled out with universal boundary conditions (III.3) at the GUT scale.…”

“…The analogs of Table I for the gauge groups SO(10) and E 6 are given in Appendix A of [18], where a detailed discussion has been presented on the phenomenological consequences of different choices of the grand unified gauge group. We note that in the present work we are not necessarily looking at very light neutralinos as the second lightest Higgs boson can be heavy, and can decay into neutralinos that are massive.…”

“…Furthermore, in the NMSSM there is a possibility of a low mass pseudoscalar in the Higgs spectrum. Thus, there is a distinct possibility of the scalar Higgs boson(s) decaying invisibly into these pseudoscalars [18].…”

Invisible Higgs decay in a supersymmetric inverse seesaw model with light sneutrino dark matter

“…In fact, this can occur in many well-motivated BSM scenarios, e.g., MSSM with neutralino DM [36][37][38][39][40][41][42][43], models with extended scalar sector [44][45][46][47][48][49], Majoron models [50][51][52][53][54], large extra dimension [55,56], etc. The possibility of Higgs decaying to DM has gained renewed interest in view of the recent claims from some DM direct detection experiments such as DAMA/LIBRA [57], CoGeNT [58], CRESST-II [59], and more recently CDMS-II [60], in favor of a light DM in the mass range 5-50 GeV, with a large DM-nucleon scattering cross section of 10 −5 − 10 −7 pb.…”