Probing unexplored spin-dependent dark matter-proton coupling with few-photoelectron threshold in COSINE-100
Year: 2026
Type: preprint
Abstract: We report new constraints on the spin-dependent scattering cross section between low-mass dark matter and protons using data collected by the COSINE-100 experiment. By implementing a specialized event selection process using a multi-layer perceptron and robust noise mitigation, this analysis pioneers a detection threshold of 3 and 4 isolated peaks, corresponding to the reconstructed photoelectrons, which are significantly lower than the 8 photoelectron threshold used in previous analyses. In this unstudied few-photoelectron regime, where instrumental noise and phosphorescence are prevalent, we utilize a phenomenological background model to search for the annual modulation signal expected from the Standard Halo Model. No statistically significant annual modulation is observed in our data. We derive new 90% confidence level (C.L.) upper limits for the spin-dependent DM-proton cross section, establishing the world's most stringent constraints in the 1.75-2.25 GeV/c$^2$ mass range. Furthermore, by incorporating the Migdal effect, we extend the experimental sensitivity to the sub-GeV/c$^2$ regime, setting world-leading limits in the 15-58 MeV/c$^2$ range. These results demonstrate the capability of NaI(Tl) target materials to probe previously unexplored regions of the dark matter parameter space.
Source: arXiv (Cornell University)
Authors: Kim, W. K., Carlin, N., Cho, J. Y., Cho, S. J., Choi, S., Ezeribe, A. C., França, L. E., Muhdi, R. F., Gileva, O., Ha, C., Hahn, I. S., Jeon, E. J., Joo, H. W., Kang, W. G., Kauer, M., Kim, B. H., Kim, D. Y., Kim, H. J., Kim, J., Kim, K. W., Kim, S. H., Kim, S. K., Kim, Y. D., Kim, Y. H., Ko, B. R., Ko, Y. J., Koh, B. C., Lee, D. H., Lee, E. K., Lee, H., Lee, H. S., Lee, H. Y., Lee, I. S., Lee, J., Lee, J. Y., Lee, M. H., Lee, S. H., Lee, S. H., Lee, Y. J., Leonard, D. S., Luan, N. T., Machado, V. H. A., Manzato, B. B., Maruyama, R. H., Olsen, S. L., Park, H. K., Park, H. S., Park, J. C., Park, J. S., Park, K. S., Park, K., Park, S. D., Pitta, R. L. C., Prihtiadi, H., Rott, C., Shin, K. A., Cavalcante, D. F. F. S., Son, M. K., Spooner, N. J. C., Truc, L. T., Yang, L., Yu, G. H.
Institutions: Institute for Basic Science, Korea University of Science and Technology, Universidade de São Paulo, Kyungpook National University, Seoul National University, University of Sheffield, State University of Malang, Chung-Ang University, University of Wisconsin–Madison, Korea University, Jeju National University, Yale University, Korea Research Institute of Standards and Science, University of Utah, University of California San Diego
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, Fundação de Amparo à Pesquisa do Estado de São Paulo, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Institute for Basic Science, Korea Hydro and Nuclear Power, Science and Technology Facilities Council
Awards: Particle Physics Consolidated Grant from the University of Sheffield - ATLAS, ATLAS upgrade, T2K, FNE, MICE, EDELWEISS/EURECA, DMGS, SNO+, R&D, KE, G2742186019, G324603001, G3592049440, G4236069184, G6292139600, G6438247056, Particle Physics Consolidated Grant from the University of Sheffield - ATLAS, ATLAS upgrade, T2K, LBNE/F, Hyper-K, MICE, LZ, DMGS, DRIFT, R&D, KE, Testing DAMA with the COSINE Experiment, G7698421209, G8269719600
OpenAlex ID: W7140294331
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