Search for direct production of charginos and neutralinos decaying via the 125 GeV Higgs boson in $\sqrt{s}$ = 8 TeV $pp$ collisions with the ATLAS detector

A search for the direct pair production of charginos and neutralinos $pp\to\tilde{\chi}_1^\pm\tilde{\chi}_2^0$ is presented, where the chargino decays via a $W$ boson $\tilde{\chi}_1^\pm\to \tilde{\chi}_1^0 (W^{\pm}\to\ell^{\pm}\nu)$, while the neutralino decays via the 125 GeV Higgs boson $\tilde{\chi}_2^0\to \tilde{\chi}_1^0 (h\to bb/\gamma\gamma/\ell^{\pm}\nu qq)$ to the lightest neutralino. The final states considered for the search have large missing transverse momentum, an isolated electron or muon, and one of the following: either two jets identified as originating from bottom quarks, or two photons, or a second electron or muon with the same electric charge. The analysis is based on 20.3 fb$^{-1}$ of $\sqrt{s}=8$ TeV proton--proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with the Standard Model expectations, and limits are set in the context of a simplified supersymmetric model within which, in the case where the $\tilde{\chi}_1^0$ is massless, the direct production of $\tilde{\chi}_1^\pm$ and $\tilde{\chi}_2^0$ of equal mass below 250 GeV is excluded.