Supersoft supersymmetry is super-safe

Abstract

We show that supersymmetric models with a large Dirac gluino mass can evade much of the jets plus missing energy searches at the LHC. Dirac gaugino masses arise from ``supersoft'' operators that lead to finite one-loop suppressed contributions to the scalar masses. A little hierarchy between the Dirac gluino mass 5--10 times heavier than the squark masses is automatic and technically natural, in stark contrast to supersymmetric models with Majorana gaugino masses. At the LHC, colored sparticle production is suppressed not only by the absence of gluino pair (or associated) production, but also because several of the largest squark pair production channels are suppressed or absent. We recast the null results from the present jets plus missing energy searches at the LHC for supersymmetry onto a supersoft supersymmetric simplified model. Assuming a massless lightest supersymmetric particle, we find the strongest bounds are as follows: 748 GeV from a $2j+{\mathrm{E\ensuremath{\llap{\not\;}}}}_{T}$ search at ATLAS ($4.7\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$) and 684 GeV from a combined jets plus missing energy search using ${\ensuremath{\alpha}}_{T}$ at CMS ($1.1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$). In the absence of a future observation, we estimate the bounds on the squark masses to improve only modestly with increased luminosity. We also briefly consider the further weakening in the bounds as the lightest supersymmetric particle mass is increased.