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Search for a Dark Matter-Induced Annual Modulation Signal in NaI(Tl) with the COSINE-100 Experiment
G Adhikari1, P Adhikari1, E Barbosa de Souza2
1Department of Physics, Sejong University, Seoul 05006, Republic of Korea.
Physical Review Letters
|August 7, 2019
Summary
The COSINE-100 experiment found no significant evidence for dark matter annual modulation. This study provides new constraints on dark matter signals using sodium iodide detectors, contributing to the ongoing search for weakly interacting massive particles.
Area of Science:
- Experimental particle physics
- Astroparticle physics
- Nuclear physics
Background:
- The DAMA/LIBRA experiment has reported a persistent annual modulation signal, interpreted as evidence for dark matter.
- Direct detection experiments aim to observe dark matter particles interacting with terrestrial detectors.
- Sodium iodide (NaI(Tl)) scintillators are a target material used in dark matter searches.
Purpose of the Study:
- To independently test the DAMA/LIBRA claim of dark matter detection.
- To search for the annual modulation signal predicted by dark matter models.
- To constrain the properties of dark matter particles through model-independent analysis.
Main Methods:
- Utilized 1.7 years of data from the COSINE-100 experiment.
- Employed 106 kg of NaI(Tl) target material with a total exposure of 97.7 kg yr.
- Analyzed data in the 2-6 keV energy region, applying a chi-squared minimization method.
Main Results:
- Observed a background rate of 2.7 cpd/kg/keV in the region of interest.
- Determined best-fit values for modulation amplitude and phase: 0.0092 ± 0.0067 cpd/kg/keV and 127.2 ± 45.9 days, respectively.
- These results provide new constraints on the dark matter annual modulation signal.
Conclusions:
- The observed modulation amplitude is consistent with the background fluctuations.
- COSINE-100 results do not support the DAMA/LIBRA's WIMP discovery claim.
- Further data collection and analysis are ongoing to improve sensitivity.
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