Search for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 5.8 fb$^{-1}$ of $\sqrt{s}=8$ TeV proton-proton collisions

Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 5.8 fb$^{-1}$ of $pp$ collision data at $\sqrt{s} = 8$ TeV collected by the ATLAS experiment at the Large Hadron Collider in 2012. The event selection requires missing transverse momentum, no isolated electrons or muons, and from $\geq$6 to $\geq$9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a simplified model containing only a gluino octet and a neutralino, where pair-produced gluinos each decay to $t+\bar{t}+\tilde{\chi}_1^0$. In this context gluino masses smaller than 1.0 TeV are excluded at the 95% CL for neutralino masses below 300 GeV.