Search for Strongly Interacting Massive Particles with Trackless Jets

A search for dark matter in the form of strongly interacting massive particles, manifesting themselves as a pair of jets without tracks in the CMS detector at the LHC, is presented. The charged energy fraction of jets is used as a key discriminator to efficiently suppress the large multijet background, and the remaining background is estimated directly from data. The search is performed using proton-proton collision data corresponding to an integrated luminosity of $16.1~\mathrm{fb}^{-1}$, collected by the CMS detector in 2016. No significant excess of events is observed above the expected background. Strongly interacting massive particles with masses up to $900~\mathrm{GeV}$ are excluded at $95\%$ confidence level for the model under consideration. The presented analysis thus evaluates the sensitivity to an unconventional phase space for new physics for the first time at colliders. In addition to the interpretation in the context of the SIMP model, model-independent limits that can be used for reinterpretation of the results are provided.