COSINE-100: Full dataset challenges the annual modulation signal of DAMA/LIBRA

For over 25 years, the DAMA/LIBRA collaboration has claimed to observe an
annual modulation signal, suggesting the existence of dark matter
interactions. However, no experiment employing different target materials
has observed a dark matter signal consistent with their result. To address
this puzzle, the COSINE-100 collaboration conducted a model-independent
test using sodium iodide crystal detectors, the same target material as
DAMA/LIBRA. Analyzing data collected over 6.4 years by the effective mass
of 61.3 kg, with improved energy calibration and time-dependent background
modeling, we found no evidence of an annual modulation signal, challenging
the DAMA/LIBRA result with a confidence level greater than 3σ. This
finding represents a substantial step toward resolving the long-standing
debate surrounding DAMA/LIBRA’s dark matter claim, indicating that the
observed modulation is unlikely to be caused by dark matter interactions.

25余年来，DAMA/LIBRA合作组始终宣称观测到年度调制信号，这暗示了暗物质相互作用的存在。然而，所有采用不同靶材料的实验均未观测到与该结果相符的暗物质信号。为解决这一谜题，COSINE-100合作组采用与DAMA/LIBRA相同的靶材料——碘化钠晶体探测器，开展了与模型无关的检验。本研究通过对有效质量61.3千克的探测器采集的6.4年数据进行分析，并辅以优化的能量标定与随时间变化的本底建模，未发现年度调制信号的存在，以高于3σ的置信水平对DAMA/LIBRA的结果提出了质疑。该研究成果为解决围绕DAMA/LIBRA暗物质宣称的长期争议迈出了重要一步，表明其所观测到的调制信号不太可能由暗物质相互作用所引发。