Ultra-long-lived particles searches with MATHUSLA

There are many theoretical motivations for long-lived particle (LLP) signals at the LHC in a comprehensive survey of Standard Model (SM) extensions. LLPs are a common prediction of a wide range of theories that address unsolved fundamental mysteries such as naturalness, dark matter, baryogenesis and neutrino masses, and represent a natural and generic possibility for physics beyond the SM (BSM). MATHUSLA (MAssive Timing Hodoscope for Ultra Stable neutraL pArticles) is a proposal for a minimally instrumented, large-volume surface detector to detect such LLPs. The MATHUSLA surface detector will consist of an air-filled decay volume surrounded by charged particles detectors (top, bottom, and sides) that provide timing and a robust multilayer tracking system located in the upper region. The collaboration proposes covering a total sensitive area of (200 × 200) square meters on the surface in the region near the interaction point of ATLAS or CMS detectors for the beginning of the HL-LHC run.