New particles with macroscopic lifetimes arise naturally in many beyond-the-standard-model scenarios. Long-lived particles are predicted by models including anomaly or gravity-mediated supersymmetry-breaking scenarios, split supersymmetry, as well as models featuring exotic decays of the Higgs boson. These particles may be key to understanding naturalness, dark matter, and other outstanding questions in particle physics. The seminar will present results from four recent ATLAS searches for long-lived particles, covering various signatures and probing lifetimes from a fraction of a nanosecond to years. A search for short tracks from charged particles sets the most restrictive limits on very compressed supersymmetric models. Three searches discussed use unconventional techniques to fill important gaps in the LHC’s sensitivity to long-lived particles decaying into leptonic or hadronic final states across the full lifetime range.
Michelangelo Mangano, Monica Pepe-Altarelli and Pedro Silva.