DAMA/LIBRA annual modulation and a later same-target COSINE-100 test

What changed

DAMA/LIBRA phase 2 reported an annual modulation of low-energy single-hit events in six annual cycles, with an exposure of 1.13 tonne-years. A phase-fixed 1–6 keV fit gave 0.0105 ± 0.0011 counts per day per kilogram per keV. A later COSINE-100 analysis with an independent sodium-iodide detector reported a phase-fixed 1–6 keV electron-equivalent amplitude of 0.0017 ± 0.0029 over 6.4 years of operation and compared its results with DAMA/LIBRA. Two additional annual cycles extended the phase-2 dataset to eight cycles and 1.53 tonne-years; the independent COSINE comparison used this later DAMA analysis.

Scientific scope

DAMA/LIBRA phase 2 reported an annual modulation of low-energy single-hit events in six annual cycles, with an exposure of 1.13 tonne-years. A phase-fixed 1–6 keV fit gave 0.0105 ± 0.0011 counts per day per kilogram per keV. A later COSINE-100 analysis with an independent sodium-iodide detector reported a phase-fixed 1–6 keV electron-equivalent amplitude of 0.0017 ± 0.0029 over 6.4 years of operation and compared its results with DAMA/LIBRA. Two additional annual cycles extended the phase-2 dataset to eight cycles and 1.53 tonne-years; the independent COSINE comparison used this later DAMA analysis. DAMA’s modulation is an experiment-specific observed signal and model-based statistical inference, not a confirmed detection of dark matter particles. Its 2018 12.9σ figure includes 20 cumulative annual cycles, including older DAMA data, and is not independent evidence from the six new cycles alone. COSINE analyzes five selected crystals with effective mass 61.3 kg and about 5.84 good-data years, rather than 106 kg for all 6.4 years. Its comparison uses fitted background models, calibration choices and quenching-factor assumptions. The authors report 3.57σ tension for 1–3 keV electron-equivalent and 3.25σ for a specified sodium nuclear-recoil comparison in the body; the summary prints 3.23σ for the latter. These are comparisons of specified signal models, not universal exclusion of dark matter. The later DAMA journal original reports eight phase-2 cycles with 1.53 tonne-years; its fixed-phase 1–3 keV amplitude is 0.0191 ± 0.0020, while 1–6 keV is 0.01048 ± 0.00090. Its 13.7σ for 2–6 keV uses 2.86 tonne-years including earlier DAMA/NaI and phase 1, with free fitted phase and period; this is not independent of the earlier result. COSINE compares against this later paper under specified calibration and analysis assumptions. The journal volume is dated 2021; journal metadata gives publication on 4 June 2022, and the paper states receipt on 15 December 2021. The two collaborations have distinct bylines; COSINE author transcription is partial. Raw detector events, full calibration and later published versions were not independently replayed.

Evidence

The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. DAMA’s modulation is an experiment-specific observed signal and model-based statistical inference, not a confirmed detection of dark matter particles. Its 2018 12.9σ figure includes 20 cumulative annual cycles, including older DAMA data, and is not independent evidence from the six new cycles alone. COSINE analyzes five selected crystals with effective mass 61.3 kg and about 5.84 good-data years, rather than 106 kg for all 6.4 years. Its comparison uses fitted background models, calibration choices and quenching-factor assumptions. The authors report 3.57σ tension for 1–3 keV electron-equivalent and 3.25σ for a specified sodium nuclear-recoil comparison in the body; the summary prints 3.23σ for the latter. These are comparisons of specified signal models, not universal exclusion of dark matter. The later DAMA journal original reports eight phase-2 cycles with 1.53 tonne-years; its fixed-phase 1–3 keV amplitude is 0.0191 ± 0.0020, while 1–6 keV is 0.01048 ± 0.00090. Its 13.7σ for 2–6 keV uses 2.86 tonne-years including earlier DAMA/NaI and phase 1, with free fitted phase and period; this is not independent of the earlier result. COSINE compares against this later paper under specified calibration and analysis assumptions. The journal volume is dated 2021; journal metadata gives publication on 4 June 2022, and the paper states receipt on 15 December 2021. The two collaborations have distinct bylines; COSINE author transcription is partial. Raw detector events, full calibration and later published versions were not independently replayed.

Contributors

• The named authors in the research record · SCIENCE: These are the listed authors of the cited contribution sources. Paper authorship does not quantify individual effort. An incomplete list is explicitly marked; same names are not automatically merged.

• First model independent results from DAMA/LIBRA–phase2
• COSINE-100 Full Dataset Challenges the Annual Modulation Signal of DAMA/LIBRA
• Further results from DAMA/LIBRA-phase2 and perspectives

Provisional WRS assessment, edition 2026-10-28.1. Independent expert calibration is pending. This grade does not certify correctness or assign ownership.

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