  A search for long-lived particles decaying to displaced, nonprompt jets and
missing transverse momentum is presented. The data sample corresponds to an
integrated luminosity of 137 fb$^{-1}$ of proton-proton collisions at a
center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC
in 2016-2018. Candidate signal events containing nonprompt jets are identified
using the timing capabilities of the CMS electromagnetic calorimeter. The
results of the search are consistent with the background prediction and are
interpreted using a gauge-mediated supersymmetry breaking reference model with
a gluino next-to-lightest supersymmetric particle. In this model, gluino masses
up to 2100, 2500, and 1900 GeV are excluded at 95% confidence level for proper
decay lengths of 0.3, 1, and 100 m, respectively. These are the best limits to
date for such massive gluinos with proper decay lengths greater than $\sim$0.5
m.

High Energy Physics - Experiment