Search for long-lived neutral particle decays using the full statistic collected in Run I with the ATLAS detector at the LHC

Many extensions of the Standard Model (SM) include neutral weakly coupled particles that can be long-lived. These long-lived particles occur in many models, included gauge-mediated extensions of the Minimal Supersymmetric Model (MSSM), MSSM with R-parity violation, inelastic dark matter and the Hidden Valley (HV) scenario. Results are presented on ATLAS searches at the LHC for scalar boson decays (including rare Higgs boson decays) to pair of neutral, long-lived hidden-sector particles that lead to final states containing fermion anti-fermion pairs or pairs of collimated lepton jets. No excess of events above the expected background has been observed for 20.3 fb$^{−1}$ of data collected in 2012 at a center of mass energy of 8TeV. Limits are presented as a function of the proper lifetime of the long-lived neutral particle.