Long-lived particle searches with the ATLAS detector
The Standard Model has been successful at LHC, with the Higgs discovery in 2012, and very little deviations seen between the observed data and the theory expectation. However, there are still many outstanding questions, which motivate searches for Beyond-the-Standard-Model (BSM) physics. BSM physics can manifest in the LHC collisions in a variety of ways; in many extension of the SM, particles can acquire macroscopic lifetimes, giving rise to novel signatures: decays away from the interaction point, tracks that don't extend into the calorimeters, for example. These provide challenges in terms of reconstruction, triggering, and background estimation. I will discuss how we look for long-lived particles with the ATLAS detector and go into detail in two searches where we either reconstruct the long-lived particle or its decay products. I will also talk about the detector upgrade intended for high-luminosity operation and the impact on long-lived searches with the ATLAS detector.
