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 $\text{objects}+{\cancel{E}}_T$, with ${\cancel{E}}_T$ 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 ${\chi }_1$, all with masses of $\lesssim 10\mathrm{GeV}$, and the generic suppression of the exotic decays of the 125 GeV Higgs boson $h_2\to h_1{h}_1$, $a_1{a}_1$ and ${\chi }_1{\chi }_1$, however. As an illustration, we study the decay topology: $h_2\to {\chi }_1{\chi }_2$, where the binolike ${\chi }_2$ decays to $h_1{\chi }_1$ or $a_1{\chi }_1$, and $h_1/a_1\to f\overline{f}$, with $f\overline{f}={\mu }^{+}{\mu }^{-}$, $b\overline{b}$. In the dimuon case ($m_{h_1/a_1}\sim 1\mathrm{GeV}$), a statistical sensitivity of $S/\sqrt{B}>6\sigma$ can be achieved easily at the 8 TeV LHC, assuming $\sigma (pp\to W{h}_2)/\sigma (pp\to W{h}_{\text{SM}})\text{Br}(h_2\to {\mu }^{+}{\mu }^{-}{\chi }_1{\chi }_1)=0.1$. In the $b\overline{b}$ case ($m_{h_1/a_1}\sim 45\mathrm{GeV}$), $600{\mathrm{fb}}^{-1}$ data at the 14 TeV LHC can lead to a statistical sensitivity of $S/\sqrt{B}>5\sigma$, assuming $\sigma (pp\to Z{h}_2)/\sigma (pp\to Z{h}_{\text{SM}})\text{Br}(h_2\to b\overline{b}{\chi }_1{\chi }_1)=0.5$. These exotic decays open a new avenue for exploring new physics couplings with the 125 GeV Higgs boson at colliders.

• Received 27 October 2013

DOI:https://doi.org/10.1103/PhysRevLett.112.221803