Dual phase (liquid/gas) xenon time projection chambers (TPCs) lead the field of direct dark matter searches, with particular sensitivity to Weakly Interacting Massive Particles (WIMPs). This is a well established technology, proven to be scalable from a few tens of kg of target mass to the current multi-tonne detectors LZ and XENONnT. These detectors have recently announced their first, world leading WIMP search results, and are expected to further improve WIMP-nucleon cross-section sensitivity by up to two orders of magnitude relatively to the previous generation. Despite the exciting prospects for these experiments, there is broad consensus in the community of the need for a larger detector, able to probe the WIMP parameter space down to the irreducible "neutrino fog”. Should the current generation of instruments provide evidence of a signal, a large detector will be essential as the nature of dark matter becomes open to exploration. With this goal in mind, the XENON, LZ and DARWIN collaborations recently formed the XLZD Consortium aiming to build and operate a xenon TPC with 40-80 tonnes of active mass, expected to start operating by the start of the next decade. The extremely low background of this detector will allow it to serve as an observatory in astroparticle physics, with high sensitivity to many other physics channels, including alternative dark matter candidates and neutrino physics through to neutrinoless double beta decay and a variety of astrophysical sources.
In this seminar, I will present an overview of the XLZD detector concept and timeline, and its initial sensitivity projections to multiple science cases, particularly focusing on WIMP and neutrinoless double beta decay searches.