G.H. Yu, N. Carlin, J.Y. Cho, J.J. Choi, S. Choi, A.C. Ezeribe, L.E. França, C. Ha, I.S. Hahn, S.J. Hollick, E.J. Jeon, H.W. Joo, W.G. Kang, M. Kauer, B.H. Kim, H.J. Kim, J. Kim, K.W. Kim, S.H. Kim, S.K. Kim, W.K. Kim, Y.D. Kim, Y.H. Kim, Y.J. Ko, D.H. Lee, E.K. Lee, H. Lee, H.Y. Lee, I.S. Lee, J. Lee, J.Y. Lee, M.H. Lee, S.H. Lee, S.M. Lee, Y.J. Lee, D.S. Leonard, N.T. Luan, V.H.A. Machado, B.B. Manzato, R.H. Maruyama, R.J. Neal, S.L. Olsen, B.J. Park, H.K. Park, H.S. Park, J.C. Park, K.S. Park, S.D. Park, R.L.C. Pitta, H. Prihtiadi, S.J. Ra, C. Rott, K.A. Shin, D.F.F.S. Cavalcante, M.K. Son, N.J.C. Spooner, L.T. Truc, L. Yang
COSINE-100 is a direct dark matter search experiment, with the primary goal of testing the annual modulation signal observed by DAMA/LIBRA, using the same target material, NaI(Tl). In previous analyses, we achieved the same 1 keV energy threshold used in the DAMA/LIBRA's analysis that reported an annual modulation signal with 11.6σ significance. In this article, we report an improved analysis that lowered the threshold to 0.7 keV, thanks to the application of Multi-Layer Perception network and a new likelihood parameter with waveforms in the frequency domain. The lower threshold would enable a better comparison of COSINE-100 with new DAMA results with a 0.75 keV threshold and account for differences in quenching factors. Furthermore the lower threshold can enhance COSINE-100's sensitivity to sub-GeV dark matter searches. © 2024 IOP Publishing Ltd and Sissa Medialab. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Department of Physics, Sungkyunkwan University, Suwon, 16419, South Korea; Center for Underground Physics, Institute for Basic Science (IBS), Daejeon, 34126, South Korea; Physics Institute, University of São Paulo, São Paulo, 05508-090, Brazil; Department of Physics, Kyungpook National University, Daegu, 41566, South Korea; Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea; Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH, United Kingdom; Department of Physics, Chung-Ang University, Seoul, 06973, South Korea; Center for Exotic Nuclear Studies, Institute for Basic Science (IBS), Daejeon, 34126, South Korea; Department of Science Education, Ewha Womans University, Seoul, 03760, South Korea; IBS School, University of Science and Technology (UST), Daejeon, 34113, South Korea; Department of Physics, Wright Laboratory, Yale University, New Haven, 06520, CT, United States; Department of Physics, Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin-Madison, Madison, 53706, WI, United States; Department of Accelerator Science, Korea University, Sejong, 30019, South Korea; Korea Research Institute of Standards and Science, Daejeon, 34113, South Korea; Department of Physics, IQS, Chungnam National University, Daejeon, 34134, South Korea; Department of Physics, Universitas Negeri Malang, Malang, 65145, Indonesia; Department of Physics and Astronomy, University of Utah, Salt Lake City, 84112, UT, United States; Department of Physics, University of California San Diego, La Jolla, 92093, CA, United States