Por Paulo Brás (LIP Coimbra).

The LUX-ZEPLIN (LZ) experiment is a dark matter detector operating at the Sanford Underground Research Facility in Lead, South Dakota, USA. Its main detector is a 7 tonne dual-phase xenon time projection chamber, built with ultra-low background materials. On July 7th 2022, LZ presented its first science results on the search for dark matter in the form of Weakly Interacting Massive Particles (WIMPs), with an exposure of 60 live-days and a target mass of 5.5 tonnes. With this first science run, LZ has achieved a world-leading limit on spin-independent WIMP-nucleon cross-section for WIMP masses above 9 GeV, reaching a limit of 6.5×10^−48 cm2 for this cross-section and for a 30 GeV WIMP mass at the 90% confidence level. LZ also achieved the best recorded energy resolution at the MeV scale for this type of detector, reaching 0.64% sigma/E at 2.6 MeV. This energy resolution plays a critical role in the searches for the never-observed neutrinoless double beta decay in Xe-136, one of the secondary goals of LZ. With only 60 live-days of data, LZ is already the most sensitive WIMP dark matter detector in the world, and it’s just starting. With the goal of reaching a final exposure of 1000 live-days, LZ will continue to push the limits on WIMP dark matter searches in the upcoming years.

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