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Constraints on inelastic dark matter from the CDEX-1B experiment

Y. F. Liang¹, L. T. Yang ^1,*, Q. Yue^1,†, K. J. Kang¹, Y. J. Li¹, H. P. An^1,2, Greeshma C.^3,‡, J. P. Chang⁴, H. Chen¹ et al. (CDEX Collaboration)

H. Chen¹, Y. H. Chen⁵, J. P. Cheng^1,6, J. Y. Cui¹, W. H. Dai¹, Z. Deng¹, Y. X. Dong¹, C. H. Fang⁷, H. Gong¹, Q. J. Guo⁸, T. Guo¹, X. Y. Guo⁵, L. He⁴, J. R. He⁵, H. X. Huang⁹, T. C. Huang¹⁰, S. Karmakar^3,‡, Y. S. Lan¹, H. B. Li^3,‡, H. Y. Li⁷, J. M. Li¹, J. Li¹, M. C. Li⁵, Q. Y. Li⁷, R. M. J. Li⁷, X. Q. Li¹¹, Y. L. Li¹, B. Liao⁶, F. K. Lin^3,‡, S. T. Lin⁷, J. X. Liu¹, R. Z. Liu¹, S. K. Liu⁷, Y. D. Liu⁶, Y. Liu⁷, Y. Y. Liu⁶, H. Ma¹, Y. C. Mao⁸, A. Mureed⁷, H. Pan⁴, N. C. Qi⁵, J. Ren⁹, X. C. Ruan⁹, M. B. Shen⁵, H. Y. Shi⁷, M. K. Singh^3,12,‡, T. X. Sun⁶, W. L. Sun⁵, C. J. Tang⁷, Y. Tian¹, H. F. Wan¹, G. F. Wang⁶, J. Z. Wang¹, L. Wang⁶, Q. Wang⁷, Q. Wang^1,2, Y. F. Wang¹, Y. X. Wang⁸, H. T. Wong^3,‡, Y. C. Wu¹, H. Y. Xing⁷, K. Z. Xiong⁵, R. Xu¹, Y. Xu¹¹, T. Xue¹, Y. L. Yan⁷, N. Yi¹, C. X. Yu¹¹, H. J. Yu⁴, X. Yu¹, M. Zeng¹, Z. Zeng¹, F. S. Zhang⁶, P. Zhang¹, P. Zhang⁵, Z. Y. Zhang¹, M. G. Zhao¹¹, J. F. Zhou⁵, Z. Y. Zhou⁹, and J. J. Zhu⁷ (CDEX Collaboration)

¹Key Laboratory of Particle and Radiation Imaging (Ministry of Education) and Department of Engineering Physics, Tsinghua University, Beijing 100084
²Department of Physics, Tsinghua University, Beijing 100084
³Institute of Physics, Academia Sinica, Taipei 11529
⁴NUCTECH Company, Beijing 100084
⁵YaLong River Hydropower Development Company, Chengdu 610051
⁶School of Physics and Astronomy, Beijing Normal University, Beijing 100875
⁷College of Physics, Sichuan University, Chengdu 610065
⁸School of Physics, Peking University, Beijing 100871
⁹Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413
¹⁰Sino-French Institute of Nuclear and Technology, Sun Yat-sen University, Zhuhai 519082
¹¹School of Physics, Nankai University, Tianjin 300071
¹²Department of Physics, Banaras Hindu University, Varanasi 221005

^*Contact author: yanglt@mail.tsinghua.edu.cn
^†Contact author: yueq@mail.tsinghua.edu.cn
^‡Participating as a member of TEXONO Collaboration.

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Phys. Rev. D 112, 112025 – Published 31 December, 2025

DOI: https://doi.org/10.1103/cyyp-7w7g

Abstract

We present limits on spin-independent inelastic weakly interacting massive particle (WIMP)-nucleus scattering using the $737.1 kg \cdot day$ dataset from the CDEX-1B experiment. Expected nuclear recoil spectra for various inelastic WIMP masses $m_{χ}$ and mass splittings $δ$ are calculated under the standard halo model. An accurate background model of CDEX-1B is constructed by simulating all major background sources. The model parameters are then determined through maximum likelihood estimation and Markov chain Monte Carlo fitting. The resulting 90% confidence level upper limits on the WIMP-nucleon cross section $σ_{n}$ exclude certain DAMA/LIBRA allowed regions: the $χ^{2} < 4$ regions for $δ < 30 keV$ at $m_{χ} = 250 GeV$ and the $χ^{2} < 9$ region for $δ < 50 keV$ at $m_{χ} = 500 GeV$ . The method is applicable to other inelastic dark matter scenarios, and the upcoming CDEX-50 experiment is expected to improve sensitivity by four orders of magnitude.

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References (78)

S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024).
G. Bertone, D. Hooper, and J. Silk, Phys. Rep. 405, 279 (2005).
E. Aprile et al. (XENON Collaboration), Phys. Rev. Lett. 131, 041003 (2023).
Z. Bo et al. (PandaX Collaboration), Phys. Rev. Lett. 134, 011805 (2025).
J. Aalbers et al. (LZ Collaboration), Phys. Rev. Lett. 135, 011802 (2025).
P. Agnes et al. (DarkSide-50 Collaboration), Phys. Rev. D 107, 063001 (2023).
R. Agnese et al. (SuperCDMS Collaboration), Phys. Rev. D 97, 022002 (2018).
E. Armengaud et al. (EDELWEISS Collaboration), Phys. Rev. D 99, 082003 (2019).
G. Angloher et al. (CRESST Collaboration), Phys. Rev. D 110, 083038 (2024).
R. Bernabei et al. (DAMA-LIBRA Collaboration), Eur. Phys. J. C 67, 39 (2010).
W. Zhao et al. (CDEX Collaboration), Phys. Rev. D 88, 052004 (2013).
S. K. Liu et al. (CDEX Collaboration), Phys. Rev. D 90, 032003 (2014).
Q. Yue et al. (CDEX Collaboration), Phys. Rev. D 90, 091701 (2014).
W. Zhao et al. (CDEX Collaboration), Phys. Rev. D 93, 092003 (2016).
L. T. Yang et al. (CDEX Collaboration), Chin. Phys. C 42, 023002 (2018).
H. Jiang et al. (CDEX Collaboration), Phys. Rev. Lett. 120, 241301 (2018).
H. Jiang et al. (CDEX Collaboration), Sci. China Phys. Mech. Astron. 62, 031012 (2018).
L. T. Yang et al. (CDEX Collaboration), Phys. Rev. Lett. 123, 221301 (2019).
Y. Wang et al. (CDEX Collaboration), Sci. China Phys. Mech. Astron. 64, 281011 (2021).
X. P. Geng et al. (CDEX Collaboration), J. Cosmol. Astropart. Phys. 07 (2024) 009.
Z. Z. Liu et al. (CDEX Collaboration), Phys. Rev. Lett. 123, 161301 (2019).
D. Tucker-Smith and N. Weiner, Phys. Rev. D 64, 043502 (2001).
J.-J. Zhang, Z.-L. Han, A. Liu, and F.-L. Shao, Nucl. Phys. B1014, 116864 (2025).
S. Chang, N. Weiner, and I. Yavin, Phys. Rev. D 82, 125011 (2010).
S. Kang, S. Scopel, and G. Tomar, Phys. Rev. D 99, 103019 (2019).
D. Baxter et al., Eur. Phys. J. C 81, 907 (2021).
J. P. Cheng et al., Annu. Rev. Nucl. Part. Sci. 67, 231 (2017).
A. Filimonova, S. Junius, L. Lopez Honorez, and S. Westhoff, J. High Energy Phys. 06 (2022) 048.
K. Agashe, Y. Cui, L. Necib, and J. Thaler, J. Cosmol. Astropart. Phys. 10 (2014) 062.
D. Kim, J.-C. Park, and S. Shin, Phys. Rev. Lett. 119, 161801 (2017).
X. Chen et al. (PandaX-II Collaboration), Phys. Rev. D 96, 102007 (2017).
P. S. Barbeau, J. I. Collar, and O. Tench, J. Cosmol. Astropart. Phys. 09 (2007) 009.
A. Soma et al., Nucl. Instrum. Methods Phys. Res., Sect. A 836, 67 (2016).
Z. She et al. (CDEX Collaboration), Phys. Rev. Lett. 124, 111301 (2020).
R. Xu et al. (CDEX Collaboration), Phys. Rev. D 106, 052008 (2022).
R. Xu et al. (CDEX Collaboration), arXiv:2403.20276.
Z. H. Zhang et al. (CDEX Collaboration), Phys. Rev. D 108, 052006 (2023).
Z. H. Zhang et al. (CDEX Collaboration), Sci. China Phys. Mech. Astron. 67, 101011 (2024).
W. H. Dai et al. (CDEX Collaboration), Phys. Rev. Lett. 129, 221802 (2022).
J. X. Liu et al. (CDEX Collaboration), arXiv:2404.09793.
Z. Y. Zhang et al. (CDEX Collaboration), Phys. Rev. Lett. 132, 171001 (2024).
Y. Wang et al. (CDEX Collaboration), Phys. Rev. D 101, 052003 (2020).
Z. Y. Zhang et al. (CDEX Collaboration), Phys. Rev. Lett. 129, 221301 (2022).
Q.-Y. Nie et al. (CDEX Collaboration), Chin. Phys. C 49, 043002 (2025).
J. Engel, Phys. Lett. B 264, 114 (1991).
J. Lewin and P. Smith, Astropart. Phys. 6, 87 (1996).
J. F. Ziegler, M. Ziegler, and J. Biersack, Nucl. Instrum. Methods Phys. Res., Sect. B 268, 1818 (2010).
J. Lindhard et al., Mat. Fys. Medd. K. Dan. Vidensk. Selsk. 33, 10 (1963), https://gymarkiv.sdu.dk/MFM/kdvs/mfm 30-39/mfm-33-10.pdf.
A. Bonhomme et al., Eur. Phys. J. C 82, 815 (2022).
J. Ma, Q. Yue, Q. Wang et al., Appl. Radiat. Isot. 127, 130 (2017).
J. Allison et al. (Geant4 Collaboration), Nucl. Instrum. Methods Phys. Res., Sect. A 835, 186 (2016).
D. MacKay, Information Theory, Inference, and Learning Algorithms, Vol. 50 (Cambridge University Press, Cambridge, England, 2003).
E. Aguayo et al. (Majorana Collaboration), Nucl. Instrum. Methods Phys. Res., Sect. A 701, 176 (2013).
I. J. Arnquist et al. (Majorana Collaboration), Eur. Phys. J. C 82, 226 (2022).
P. Virtanen, R. Gommers, T. E. Oliphant et al., Nat. Methods 17, 261 (2020).
D. Foreman-Mackey, D. W. Hogg, D. Lang, and J. Goodman, Publ. Astron. Soc. Pac. 125, 306 (2013).
J. Angle et al. (XENON Collaboration), Phys. Rev. Lett. 100, 021303 (2008).
J. Angle et al. (XENON10 Collaboration), Phys. Rev. D 80, 115005 (2009).
F. J. Petriello and K. M. Zurek, J. High Energy Phys. 09 (2008) 047.
E. Armengaud et al. (EDELWEISS Collaboration), Phys. Lett. B 702, 329 (2011).
E. Aprile et al. (XENON Collaboration), Phys. Rev. Lett. 121, 111302 (2018).
E. Adams et al. (PICO Collaboration), Phys. Rev. D 108, 062003 (2023).
Y. Meng et al. (PandaX-4T Collaboration), Phys. Rev. Lett. 127, 261802 (2021).
D. S. Akerib et al. (CDMS Collaboration), Phys. Rev. Lett. 93, 211301 (2004).
Z. Ahmed et al. (CDMS Collaboration), Phys. Rev. Lett. 102, 011301 (2009).
Z. Ahmed et al. (CDMS Collaboration), Phys. Rev. D 83, 112002 (2011).
D. Tucker-Smith and N. Weiner, Phys. Rev. D 72, 063509 (2005).
G. Angloher et al., Astropart. Phys. 18, 43 (2002).
G. Angloher et al., Astropart. Phys. 23, 325 (2005).
G. Angloher et al. (CRESST Collaboration), Eur. Phys. J. C 76, 25 (2016).
J. Bramante, P. J. Fox, G. D. Kribs, and A. Martin, Phys. Rev. D 94, 115026 (2016).
G. J. Alner et al. (UK Dark Matter Collaboration), Astropart. Phys. 23, 444 (2005).
D. Y. Akimov et al. (ZEPLIN-III Collaboration), Phys. Lett. B 692, 180 (2010).
R. Bernabei et al., in 4th International Conference on Physics Beyond the Standard Model: Beyond the Desert (BEYOND 03) (Springer, New York, 2003), pp. 541–560.
R. Bernabei et al., Eur. Phys. J. C 23, 61 (2002).
R. Bernabei et al. (DAMA Collaboration), Eur. Phys. J. C 56, 333 (2008).
M. Pospelov, N. Weiner, and I. Yavin, Phys. Rev. D 89, 055008 (2014).
S. Scopel and K.-H. Yoon, J. Cosmol. Astropart. Phys. 02 (2016) 050.

Phys. Rev. D 112, 112025– Published 31 December, 2025

Vol. 112, Iss. 11 — 1 December 2025

Received 10 October 2025
Accepted 15 December 2025

DOI: https://doi.org/10.1103/cyyp-7w7g

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

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Constraints on inelastic dark matter from the CDEX-1B experiment

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