Targeting Low Energy Leptons in High Energy Physics: A Search for Compressed Mass-States Beyond the Standard Model

A search for compressed mass-states using low-momentum prompt and displaced leptons and missing transverse momentum is performed utilizing data collected from proton-proton collisions at √ s = 13 TeV collected during the three-year period from 2016-2018 by the CMS collaboration at the LHC. The results are interpreted in the context of theories predicting a hypothetical weakly interacting massive particle (WIMP), which originates from the decay of another new particle with a mass slightly larger than that of the WIMP candidate. Additional products of the decay process may include one or two leptons. Additionally, the results are interpreted in scenarios where the new physics state may be long-lived, leaving a displaced signature in the detector.