  A cluster of soft displaced tracks corresponds to the dark matter
co-annihilation regime. The long-lived regime is, in particular, motivated by
the unexplored top partner physics. The background in this regime is extremely
challenging to model using a traditional simulation method. We demonstrate the
feasibility of handling the formidable background using the CMS Open Data. We
perform this analysis to search for compressed and long-lived top partners in
the 8 TeV CMS Open Data events with the integrated luminosity of 11.6 fb$^{-1}$
and obtain new limits. With 15-30 GeV mass splitting between the top partner
and the DM candidate, we exclude the top partner mass below 350 GeV, which is
more stringent than the ATLAS and CMS results using 8 TeV data with 20
fb$^{-1}$ luminosity. Our study also shows that the CMS Open Data can be a
powerful tool to help physicists explore non-conventional new physics and even
enable deriving new limits on exotic signals from data directly.
