Supersymmetric Exotic Decays of the 125 GeV Higgs Boson

Abstract

We reveal a set of novel decay topologies for the 125 GeV Higgs boson in supersymmetry which are initiated by its decay into a pair of neutralinos, and discuss their collider search strategies. This category of exotic Higgs decays is characterized by the collider signature: visible objects þ E T , with E T dominantly arising from escaping dark matter particles. Their benchmark arises naturally in the Peccei-Quinn symmetry limit of the minimal supersymmetric standard model singlet extensions, which is typified by the coexistence of three light particles: singletlike scalar h 1 and pseudoscalar a 1 , and singlinolike neutralino χ 1 , all with masses of ≲10 GeV, and the generic suppression of the exotic decays of the 125 GeV Higgs boson h 2 → h 1 h 1 , a 1 a 1 and χ 1 χ 1 , however. As an illustration, we study the decay topology: h 2 → χ 1 χ 2 , where the binolike χ 2 decays to h 1 χ 1 or a 1 χ 1 , and h 1 =a 1 → ff, with ff ¼ μ þ μ − , bb. In the dimuon case (m h 1 =a 1 ∼ 1 GeV), a statistical sensitivity of S= ffiffiffi ffi B p > 6σ can be achieved easily at the 8 TeV LHC, assuming σðpp → Wh 2 Þ=σðpp → Wh SM ÞBrðh 2 → μ þ μ − χ 1 χ 1 Þ ¼ 0.1. In the bb case (m h 1 =a 1 ∼ 45 GeV), 600 fb −1 data at the 14 TeV LHC can lead to a statistical sensitivity of S= ffiffiffi ffi B p > 5σ, assuming σðpp → Zh 2 Þ=σðpp → Zh SM ÞBrðh 2 → bbχ 1 χ 1 Þ ¼ 0.5. (SUSY). The Higgs mass stabilization mechanism generally manifests itself through Higgs couplings absent in the standard model (SM). The 125 GeV Higgs boson therefore is expected to be a leading window into NP.Because the 125 GeV SM Higgs decay width is small (Γ ∼ 4 MeV), a new coupling between the Higgs boson and some light particles may lead to a large exotic Higgs decay branching fraction. The current bounds on such channels are still weak: a branching fraction as large as ∼60% is allowed at the 2σ C.L. [3][4][5][6][7], in a general context, e.g., if new physics is allowed to enter the Higgs-glue-glue coupling. If SM couplings are assumed, theorist-performed fits constrain the invisible branching fraction to be ≲25% at 95% C.L. [3,4]. Even with the full 300 fb −1 of the 14 TeV LHC, the projected upper bound is ∼10% at the 2σ C.L. on such channels [8] (mainly driven by estimates of systematic errors), which still leaves appreciable room for an exotic decay mode. Searches for exotic decays are therefore very natural and effective tools to explore possible and exciting new couplings to the 125 GeV Higgs boson.Exotic Higgs decays are often grouped into two categories according to their collider signatures: (1) purely E T and (2) visible objects (no E T , except for neutrinos from heavy quark or tau decays). Case (1) is mainly dark matter (DM) motivated and was originally studied in [9]. A well-known example for case (2) is the R-symmetry limit of the next-tominimal supersymmetric standard model (NMSSM) [10], in which the SM-like Higgs can significantly decay to a pair of light singletlike R axions (a 1 ).Separately, there is the deep cosmic mystery of DM. In the past decade...

Supersymmetric subelectroweak scale dark matter, the Galactic Center gamma-ray excess, and exotic decays of the 125 GeV Higgs boson

“…1, considering its novelty and its favoredness by kinematics. For h 1 , a 1 1 GeV, the corresponding decay h 2 → µ + µ − E T is easy to identify at the LHC with a specialized muon-jet identification procedure, which we detailed in [1] and has been highlighted as one of the highly motivated exotic Higgs searches within the 7 and 8 TeV data set of the LHC in ref. [67].…”

“…As presented in two Letters [1,2], the Peccei-Quinn symmetry limit of singlet extensions of the Minimal Supersymmetric Standard Model (MSSM) encompasses rich Higgs and dark matter (DM) physics, whose phenomenology and collider signatures we began exploring in [1]. The singlet extensions, like the next-to-MSSM (NMSSM) [3] and nearly-MSSM (nMSSM) [4], are traditionally motivated as possible solutions to the notorious µ problem in the MSSM and give rise to some limited scenarios for exotic Higgs decays and DM phenomenology.…”

“…This connection between DM physics and exotic Higgs decays in the PQ symmetry limit scenario was explicitly explored in Ref. [1] for two benchmark models that gave rise to two distinct exotic Higgs signatures of µ + µ − E T and bb E T from the 125 GeV Higgs decay. In this work, we will continue exploring this * Electronic address: jinruih@lanl.gov † Electronic address: taoliu@ust.hk ‡ Electronic address: liantaow@uchicago.edu § Electronic address: felixyu@fnal.gov connection between DM physics and Higgs collider phenomenology with two new benchmarks.…”

Exotic decays of the 125 GeV Higgs boson at future e + e − colliders

“…Many SUSY models which motivate Higgs invisible decays also induce this decay channel, e.g. [38,39]. It also commonly exists in the so-called "stealth SUSY" models [40].…”

A tale of two portals: testing light, hidden new physics at future e + e − colliders

“…These exotic decays can also give fully visible and semi-visible signatures [8,[71][72][73][74][75] when theK or S particle decays to SM final states, which provide additional handles for Higgs collider phenomenology. Those references concentrate on the scenario where the decay to SM final states are dominant, e.g.…”