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

A search for long-lived particles at the electroweak scale, which are predicted by a number of theories beyond the Standard Model, such as long-lived gluino in Split Supersymmetry, is pre- sented. The search uses 32.8 $\rm{fb}^{−1}$ of 13 TeV $pp$ collision data collected by the ATLAS detector at the LHC, and explores a multi-track vertex displaced from the collision point of proton-proton beams. The observed yield is consistent with the expectation from the background only hypoth- esis, resulting in 95% confidence-level exclusion of the long-lived gluino with masses up to 2.37 TeV at around $\tau = 0.17$ ns