Improving ANAIS-112 sensitivity to DAMA/LIBRA signal with machine learning techniques

Abstract

The DAMA/LIBRA observation of an annual modulation in the detection rate compatible with that expected for dark matter particles from the galactic halo has accumulated evidence for more than twenty years. It is the only hint of a direct detection of the elusive dark matter, but it is in strong tension with the negative results of other very sensitive experiments, requiring ad-hoc scenarios to reconcile all the present experimental results. Testing the DAMA/LIBRA result using the same target material, NaI(Tl), removes the dependence on the particle and halo models and is the goal of the ANAIS-112 experiment, taking data at the Canfranc Underground Laboratory in Spain since August 2017 with 112.5 kg of NaI(Tl). At very low energies, the detection rate is dominated by non-bulk scintillation events and careful event selection is mandatory. This article summarizes the efforts devoted to better characterize and filter this contribution in ANAIS-112 data using a boosted decision tree (BDT), trained for this goal with high efficiency. We report on the selection of the training populations, the procedure to determine the optimal cut on the BDT parameter, the estimate of the efficiencies for the selection of bulk scintillation in the region of interest (ROI), and the evaluation of the performance of this analysis with respect to the previous filtering. The improvement achieved in background rejection in the ROI, but moreover, the increase in detection efficiency, push the ANAIS-112 sensitivity to test the DAMA/LIBRA annual modulation result around 3$\sigma$ with three-year exposure, being possible to reach 5$\sigma$ by extending the data taking for a few more years than the scheduled 5 years which were due in August 2022.

References in corpus (21)

• Results from a search for dark matter in the complete LUX exposure
• First results from DAMA/LIBRA and the combined results with DAMA/NaI
• Dark Matter Results From 54-Ton-Day Exposure of PandaX-II Experiment
• New results from DAMA/LIBRA
• First Dark Matter Search Results from the LUX-ZEPLIN (LZ) Experiment
• Search for Low-Mass WIMPs with SuperCDMS
• Dark Matter Search Results from the Complete Exposure of the PICO-60 C${}_3$F${}_8$ Bubble Chamber
• Current status of direct dark matter detection experiments
• Searching for low-mass dark matter particles with a massive Ge bolometer operated above-ground
• First results on dark matter annual modulation from ANAIS-112 experiment
• Search for dark matter at colliders
• Indirect dark matter searches in Gamma- and Cosmic Rays
• Search for Electronic Recoil Event Rate Modulation with 4 Years of XENON100 Data
• Three-year annual modulation search with COSINE-100
• Optimizing EDELWEISS detectors for low-mass WIMP searches
• Search for Low-Mass Dark Matter with CsI(Tl) Crystal Detectors
• High sensitivity characterization of an ultra-high purity NaI(Tl) crystal scintillator with the SABRE proof-of-principle detector
• Probing spin-dependent dark matter interactions with ${}^6$Li
• Quenching Factor consistency across several NaI(Tl) crystals
• Machine-learning techniques applied to three-year exposure of ANAIS-112
• Long term measurement of the ${}^{222}$Rn concentration in the Canfranc Underground Laboratory

Cited by in corpus (9)

• Nonproportionality of NaI(Tl) Scintillation Detector for Dark Matter Search Experiments
• Combined Annual Modulation Dark Matter Search with COSINE-100 and ANAIS-112
• The SABRE South Technical Design Report Executive Summary
• Progress in End-to-End Optimization of Detectors for Fundamental Physics with Differentiable Programming
• Towards a Robust Model-Independent Test of the DAMA/LIBRA Dark Matter Signal: ANAIS-112 Results with Six Years of Data
• Insights into Dark Matter Direct Detection Experiments: Decision Trees versus Deep Learning
• Bayesian technique to combine independently-trained Machine-Learning models applied to direct dark matter detection
• Characterisation of Hamamatsu R11065-20 PMTs for use in the SABRE South NaI(Tl) Crystal Detectors
• Photomultiplier Requirements and Pre-Calibration for the SABRE South Liquid Scintillator Veto