LUX-ZEPLIN Sets New WIMP Limits, Detects Solar Neutrinos with Unmatched Sensitivity

December 8, 2025
LUX-ZEPLIN Sets New WIMP Limits, Detects Solar Neutrinos with Unmatched Sensitivity
  • Solar neutrino signals are detected, contributing to the broader neutrino physics program.

  • The latest analysis of the largest dark-matter dataset finds no evidence for WIMPs in the 3–9 GeV/c2 range, while extending sensitivity for higher masses and tightening theoretical scenarios.

  • Specifically, the study sets the strongest constraints to date on low-mass WIMPs within the 3–9 GeV/c2 window.

  • Results were presented at SURF and prepared for arXiv and Physical Review Letters, refining the understanding of dark-matter properties and interactions.

  • LZ has set world-leading WIMP limits and achieved the first solar-neutrino detection with the experiment, marking a milestone in sensitivity.

  • Solar boron-8 neutrinos are detected via coherent elastic neutrino-nucleus scattering in xenon, offering a new avenue to study solar neutrinos.

  • The study probes low-mass WIMPs as dark-matter candidates while confirming boron-8 solar neutrino interactions with xenon, aiming to sharpen the ability to distinguish potential dark-matter signals from neutrino events.

  • LLNL researchers, including Rachel Mannino, lead data acquisition, calibration, and background mitigation, shaping the experiment's calibration and analysis strategy.

  • LZ remains the most sensitive direct-detection dark matter experiment and is poised for potential discovery, with results validating its enhanced performance and expanded reach into new dark matter models.

  • A longer second run is planned to begin in 2028, expected to last about 1,000 days, to boost chances of detecting rare events and to explore physics beyond the Standard Model.

  • LUX-ZEPLIN conducted a 417-day run from spring 2023 to spring 2025 using a liquid xenon chamber to search for dark matter and observe solar neutrinos.

  • The team emphasizes the value of negative results, which refine models and guide future experiments rather than indicating failure.

  • The neutrino observations reached 4.5 sigma confidence, improving on prior sub-3-sigma results and helping reduce false positives in future dark-matter searches.

  • Neutrino observations create a background—referred to as a neutrino fog—for low-mass dark matter searches, while also enriching neutrino physics and solar fusion studies.

  • The experiment detects solar boron-8 neutrinos with unprecedented sensitivity, underscoring the neutrino fog concept in low-mass dark-matter searches.

  • LZ’s ongoing program aims to reach over 1,000 live days by 2028, broaden sensitivity to higher mass ranges (100 GeV/c2 to 100 TeV/c2), and lower energy thresholds to probe lighter dark matter, while reducing backgrounds.

  • Future plans include collecting more than 1,000 additional days by 2028 to enhance sensitivity across a broad mass range and pursue exotic dark-matter interactions and next-generation detectors studying neutrinos.

  • The detector uses 10 tons of ultrapure liquid xenon to capture nuclear recoils from potential WIMPs and signals from solar neutrinos, with energy deposition measured via light and ionization.

  • The 10-ton xenon detector sits deep underground, shielded to minimize background, recording both dark-matter interactions and boron-8 solar-neutrino signals.

  • Brown University researchers contributed by leading neutron calibration, developing detector hardware (PMT arrays), and building machine-learning tools to separate signals from background.

  • The analysis used data from March 2023 to April 2025, totaling 417 live days, focusing on probing WIMPs below 9 GeV/c2 for the first time in LZ.

  • No definitive evidence for low-mass WIMPs was found, despite enhanced sensitivity and detector improvements.

Summary based on 3 sources


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