Beyond-the-Standard-Model physics searches with LEGEND-1000

We present Beyond-the-Standard-Model (BSM) physics searches accessible to LEGEND-1000, a future neutrinoless double-beta decay (0νββ) experiment with the goal of 10 ton-years exposure. LEGEND-1000 will comprise a ton of High-purity Germanium detectors, enriched to more than 90% in 76Ge, surrounded by a 300 t of liquid argon (LAr) instrumented as an active radiation shield.
With its large exposure, low background and excellent energy resolution, LEGEND-1000 can study a broad range of BSM physics. These include searches for dark matter WIMPs or axions; symmetry violations, exotic fermions and bosons that distort the shape of the two-neutrino double-beta decay spectrum; and tests of fundamental principles, including the electron decay and the Pauli exclusion principle. Backgrounds from 39Ar and 42Ar can be mitigated by using LAr from an underground source near the detectors, enabling BSM physics searches at low energy. The LAr volume can also be considered as a target volume in many BSM searches and enhance the sensitivity of LEGEND-1000.
In this poster we will present these BSM searches and their motivations, as well as the dominant backgrounds and mitigation strategies.