The LIP Dark Matter group joined the LUX experiment in 2010 and it is a founding member of the LUX-ZEPLIN (LZ) international collaboration. These two experiments search for dark matter in the form of Weakly Interacting Massive Particles (WIMPs), aiming at their direct detection with two-phase xenon Time Projection Chambers (TPCs).

LUX (Large Underground Xenon) is a retired experiment based on a 250 kg xenon TPC that has published three previously world leading limits on the spin-independent cross section for WIMP-nucleon scattering in the 5-1000 GeV mass range. The analysis of the science and calibration data accumulated by LUX have continued even after its decommission in 2017, resulting in over 20 papers already published or in preparation. These papers cover a large variety of topics including the search of axions, sub-GeV dark matter particles and Xe isotopes rare decays, as well as innovative calibration techniques, several aspects of the physics of xenon as detector medium and the detector performance.

LUX-ZEPLIN (LZ) is a second-generation dark matter direct detection experiment that will be deployed at the 4850-feet level of the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. The LZ detector uses 7 tonnes active mass of purified xenon in a dual phase TPC to search for potential signals from WIMPs. With 5.6 tonnes fiducial mass and a 1000 live-days long dark matter search, the projected spin-independent cross section sensitivity is 1.6 x 10⁴⁸ cm²  for a 40 GeV WIMP mass, about 50 times better than the current best limit. LZ parts have started to arrive at SURF in 2018 and the detector and ancillary systems have started to be assembled. The underground deployment of LZ is scheduled for 2019 and commissioning is expected to start in the beginning of 2020. In parallel with the detector construction and deployment, an intense activity of simulation, R&D of data analysis tools, their implementation and validation is taking place.

Photos

Group Leader:  

Isabel Lopes

isabel@coimbra.lip.pt