Search for long-lived, massive particles in events with displaced vertices and missing transverse momentum in 13 TeV $pp$ collisions with the ATLAS detector

A search for long-lived, massive particles, as generically predicted by many theories beyond the Standard Model, is presented. The search targets final states with large missing transverse momentum and at least one high-mass displaced vertex with five or more tracks, and used 32.7 fb$^{−1}$ of $\sqrt{s}=13$ TeV pp collision data collected by the ATLAS detector at the LHC. The observed yield is consistent with the expected background. The observed yield is consistent with the expected background. The results are used to extract 95% CL exclusion limits on the production of long-lived gluinos with masses up to 2.2 TeV in a simplified model inspired by Split Supersymmetry.