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 are characterized by the collider signature: visible objects + $\mbox{${\not\! E}_{\rm T}$}$, with $\mbox{${\not\! E}_{\rm T}$}$ dominantly arising from escaping dark matter particles. Their benchmark arises naturally in the Peccei-Quinn symmetry limit of the MSSM singlet-extensions, which is typified by the co-existence of three light particles: singlet-like scalar $h_1$ and pseudoscalar $a_1$, and singlino-like neutralino $\ddot{I}{‡}_1$, all with masses of $\lesssim 10$ GeV, and the generically suppression of the exotic decays of the 125 GeV Higgs boson $h_2\to h_1{h}_1$, $a_1{a}_1$ and $\ddot{I}{‡}_1\ddot{I}{‡}_1$, however. As an illustration, we study the decay topology: $h_2\to \ddot{I}{‡}_1\ddot{I}{‡}_2$, where the bino-like $\ddot{I}{‡}_2$ decays to $h_1\ddot{I}{‡}_1$ or $a_1\ddot{I}{‡}_1$, and $h_1/a_1\to f\bar{f}$, with $f\bar{f}=\hat{I}{¼}^{+}\hat{I}{¼}^{-}$, $b\bar{b}$. In the di-muon case ($m_{h_1/a_1}\sim 1$ GeV), a statistical sensitivity of $\frac{S}{\sqrt{B}}>6\ddot{I}ƒ$ can be achieved easily at the 8 TeV LHC, assuming $\frac{\ddot{I}ƒ(pp\to W{h}_2)}{\ddot{I}ƒ(pp\to W{h}_{\mathrm{SM}})}\mathrm{Br}(h_2\to \hat{I}{¼}^{+}\hat{I}{¼}^{-}\ddot{I}{‡}_1\ddot{I}{‡}_1)=0.1$. In the $b\bar{b}$ case ($m_{h_1/a_1}\sim 45$ GeV), 600 fb${}^{-1}$ data at the 14 TeV LHC can lead to a statistical sensitivity of $\frac{S}{\sqrt{B}}>5\ddot{I}ƒ$, assuming $\frac{\ddot{I}ƒ(pp\to Z{h}_2)}{\ddot{I}ƒ(pp\to Z{h}_{\mathrm{SM}})}\mathrm{Br}(h_2\to b\bar{b}\ddot{I}{‡}_1\ddot{I}{‡}_1)=0.5$. These exotic decays open a new avenue for exploring new physics couplings with the 125 GeV Higgs boson at colliders.

6 pages, 4 figures, final version for Phys. Rev. Lett