  In this work, we consider the case of a strongly coupled dark/hidden sector,
which extends the Standard Model (SM) by adding an additional non-Abelian gauge
group. These extensions generally contain matter fields, much like the SM
quarks, and gauge fields similar to the SM gluons. We focus on the exploration
of such sectors where the dark particles are produced at the LHC through a
portal and undergo rapid hadronization within the dark sector before decaying
back, at least in part and potentially with sizeable lifetimes, to SM
particles, giving a range of possibly spectacular signatures such as emerging
or semi-visible jets. Other, non-QCD-like scenarios leading to soft unclustered
energy patterns or glueballs are also discussed. After a review of the theory,
existing benchmarks and constraints, this work addresses how to build
consistent benchmarks from the underlying physical parameters and present new
developments for the PYTHIA Hidden Valley module, along with jet substructure
studies. Finally, a series of improved search strategies is presented in order
to pave the way for a better exploration of the dark showers at the LHC.
