Search for dark matter in models with a very light Z’

We present a search for the unique signature of dark matter production using a few GeV-scale Z’ boson, using the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC). In this model, dark matter produced in proton-proton collisions, radiates a light Z’. Due to the large mass difference between the Z’ and the dark matter, this radiated Z’ is boosted. The boosted Z’ decays manifests as a thin low-multiplicity jet. The two main backgrounds in this study, are jets produced in association with W and Z bosons. The normal quark and gluon jets in these events on occasion fragment anomalously, resulting in low multiplicity jets.