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7h ago

LUX‑ZEPLIN Records One Unexplained Event That Fits a Heavy WIMP

The LZ team says a lone nuclear‑recoil recorded in its dataset is consistent with a roughly 200 GeV WIMP at 2.6 sigma, and it calls for more data and outside confirmation.

Have scientists discovered a dark matter particle?
This handout image obtained and released on March 18, 2025 by the ESA/Euclid/Euclid Consortium/NASA shows space telescope Euclid�s new image of examples of galaxies in different shapes, during Euclid first observations of the Deep Field areas. On March 19, 2025, the European space telescope Euclid, a veritable �detective of the dark universe� aided by AI and humans, delivered the first data from a mission designed to help unravel the mystery of dark matter and dark energy.
Image
To search for dark matter, LZ uses photomultiplier tubes (shown here before installation in the detector) to capture light from particle interactions. Image credit: Matthew Kapust / Sanford Underground Research Laboratory.

Overview

  • The collaboration found a single unexplained nuclear‑recoil event that was recorded on June 16, 2023 during an analysis of 220 live days of data collected between March 2023 and April 2024.
  • The signal passes extensive internal background checks and sits at 2.6 sigma, a level the team describes as intriguing but far below the 5‑sigma standard needed to claim a particle discovery.
  • If the event were caused by dark matter, the analysis indicates a WIMP with mass near or above 200 GeV would fit the recoil energy and timing seen in the detector.
  • The result follows an expanded search that looked for higher‑energy nuclear recoils and months of additional scrutiny; the team presented the work at the 2026 TeV Particle Astrophysics conference and submitted a paper to Physical Review Letters.
  • LZ is collecting and analyzing new data, continuing background studies, and the field is awaiting independent checks from other xenon experiments before the anomaly can be confirmed or ruled out.