  A search for long-lived particles was performed with data corresponding to an
integrated luminosity of 2.6 fb$^{-1}$ collected at a center-of-mass energy of
13 TeV by the CMS experiment in 2015. The analysis exploits two customized
topological trigger algorithms, and uses the multiplicity of displaced jets to
search for the presence of a signal decay occurring at distances between 1 and
1000 mm. The results can be interpreted in a variety of different models. For
pair-produced long-lived particles decaying to two b quarks and two leptons
with equal decay rates between lepton flavors, cross sections larger than 2.5
fb are excluded for proper decay lengths between 70-100 mm for a long-lived
particle mass of 1130 GeV at 95% confidence. For a specific model of
pair-produced, long-lived top squarks with R-parity violating decays to a b
quark and a lepton, masses below 550-1130 GeV are excluded at 95% confidence
for equal branching fractions between lepton flavors, depending on the squark
decay length. This mass bound is the most stringent to date for top squark
proper decay lengths greater than 3 mm.
