A Search for Supersymmetry in Events with a Z Boson, Jets, and Missing Transverse Energy in $pp$ Collisions with $\sqrt{s}$=13 TeV with the ATLAS Detector

A search for new phenomena in final states containing a $Z$ boson decaying to electrons or muons, jets, and large missing transverse momentum is presented. This search uses proton--proton collision data collected during 2015 and 2016 at a center of mass energy $\sqrt{s}=13$~\TeV\ by the ATLAS detector at the Large Hadron Collider, which correspond to an integrated luminosity of \lumi. The search targets the pair production of supersymmetric particles, squarks or gluinos, which decay via jets and a $Z$ boson to the lightest Supersymmetric particle, which does not interact with the ATLAS detector. Results are interpreted in simplified models of gluino-pair (squark-pair) production, and provide sensitivity to gluinos (squarks) with masses as large as~1.3~(1.0)~\TeV.