ANAIS-112 three years data: a sensitive model independent negative test of the DAMA/LIBRA dark matter signal

TL;DR

The ANAIS-112 experiment analyzed three years of data with improved methods, finding no evidence of annual modulation and challenging DAMA/LIBRA's dark matter signal at nearly 3σ confidence level.

Contribution

This work provides a sensitive, model-independent test of the DAMA/LIBRA modulation signal using the same NaI(Tl) target material with enhanced analysis techniques.

Findings

No modulation detected in three years of data

Results are inconsistent with DAMA/LIBRA at nearly 3σ

Potential to reach 5σ sensitivity within 8 years

Abstract

Weakly interacting massive particles (WIMPs) are well-motivated candidates for dark matter. One signature of galactic WIMPs is the annual modulation expected in a detector's interaction rate, which arises from Earth's revolution around the Sun. Over two decades, the DAMA/LIBRA experiment has observed such modulation with 250 kg of NaI(Tl) scintillators, in accordance with WIMP expectations but inconsistent with the negative results of other experiments. The signal depends on the target material, so to validate or refute the DAMA result, the experiment must be replicated using the same material. This is the goal of the ANAIS-112 experiment, currently underway since August 2017 with 112.5 kg of NaI(Tl). In this work, we present a reanalysis of three years of data employing an improved analysis chain to enhance the experimental sensitivity. The results presented here are consistent with the absence of modulation and inconsistent with DAMA's observation at nearly 3$\sigma$ confidence level, with the potential to reach a 5$\sigma$ level within 8 years from the beginning of the data collection. Additionally, we explore the impact of different scintillation quenching factors in the comparison between ANAIS-112 and DAMA/LIBRA.