Searches for long-lived particles, lepton-jets, stable and meta-stable particles with the ATLAS detector

Several extensions of the Standard Model like supersymmetric scenarios predict the existence of massive long-lived particles, and some of these postulate the existence of a hidden sector of particles. We report on searches for production of long-lived particles resulting in displaced vertices, abnormal specific energy loss, appearing or disappearing tracks, or collimated lepton-jets. The talk presents results of analyses using data recorded in 2012 at sqrt(s)= 8 TeV centre-of-mass energy by the ATLAS experiment at the LHC.