What produces the DAMA/LIBRA annual modulation? · revision history
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Accepted · first revision · record
- Title
- What produces the DAMA/LIBRA annual modulation?
- Plain
- DAMA/LIBRA sees a yearly rise and fall in low-energy events, peaking in late May or early June, but identical-material experiments see nothing. The question is what physical or instrumental effect makes the DAMA rate oscillate.
- Precise
- DAMA/NaI plus DAMA/LIBRA phases 1 and 2 report a single-hit residual rate in NaI(Tl) with amplitude about 0.01 cpd/kg/keV in 2-6 keV electron-equivalent energy (phase 2 alone extends this to 1-6 keV), period 1 yr and phase in late May, consistent within errors with the June 2 dark matter expectation, at $13.7\sigma$ for 2.86 t yr (2021) and $15.3\sigma$ for 3.40 t yr (2026). COSINE-100 and ANAIS-112, with the same target, find amplitudes consistent with zero. An answer identifies the source of the DAMA modulation (dark matter with crystal-specific response, an environmental or detector effect, or an analysis artifact) and demonstrates it quantitatively on DAMA data or an equivalent setup.
- Settled by
- Reproduction or elimination of the modulation in a NaI(Tl) setup that matches DAMA's crystals, energy calibration and analysis, together with release and independent analysis of DAMA's absolute rate time series.
- Kind
- phenomenon
- Answer type
- mechanism
- References
- (empty)
- Literature status
- contested
- Status note
- In 2025 COSINE-100 and ANAIS-112 combined 3-year data gave amplitudes $-0.0002 \pm 0.0026$ $\left(1-6\,\mathrm{keV}\right)$ and $0.0021 \pm 0.0028\,\mathrm{cpd}/\mathrm{kg}/\mathrm{keV}$ $\left(2-6\,\mathrm{keV}\right)$, and their 6-year data gave $0.0005 \pm 0.0019$ and $0.0027 \pm 0.0021$, excluding DAMA at $4.7\ \text{and}\ 3.5\,\sigma$; DAMA reported $15.3\,\sigma$ in $2-6\,\mathrm{keV}$ with $3.40\,\mathrm{t}\,\mathrm{yr}$ in 2026 (Nucl. Phys. At. Energy 27, 2026) and identifies no systematic.
- Posed since
- 1998