- Physical Review Journals
All JournalsPhysics Magazine

Physical Review D

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Open Access

Direct-detection constraints on inelastic dark matter with a scalar mediator

I. V. Voronchikhin1,2,* and D. V. Kirpichnikov1,†

  • *Contact author: i.v.voronchikhin@gmail.com
  • †Contact author: dmbrick@gmail.com
PDF

Phys. Rev. D 114, 055054 – Published 29 September, 2026

DOI: https://doi.org/10.1103/jy18-2dm6

Abstract

We phenomenologically calculate direct-detection constraints on inelastic dark matter (DM) for a scalar portal scenario with leptophilic couplings. The p-wave velocity suppression of the annihilation cross section of scalar-mediated inelastic Dirac DM implies the opening of viable regions of DM parameter space in the MeV-GeV mass range. Xenon-based experiments can provide a constraints on scalar-mediated inelastic fermion dark matter for sub-MeV mass splitting, via endothermic and exothermic spin-independent DM-electron scattering. To estimate the relevant constraints, we use public data from the XENON1T, PandaX-4T, and LUX-ZEPLIN liquid-xenon experiments that measure ionization electron signals.

View figure in article

Physics Subject Headings (PhySH)

Article Text

References (98)

  1. N. Aghanim et al. (Planck Collaboration), Planck 2018 results. VI. Cosmological parameters, Astron. Astrophys. 641, A6 (2020); 652, C4(E) (2021).
  2. Gianfranco Bertone and Dan Hooper, History of dark matter, Rev. Mod. Phys. 90, 045002 (2018).
  3. E. Aprile et al. (XENON Collaboration), Dark matter search results from a one Ton-Year exposure of XENON1T, Phys. Rev. Lett. 121, 111302 (2018).
  4. Yue Meng et al. (PandaX-4T Collaboration), Dark matter search results from the PandaX-4T commissioning run, Phys. Rev. Lett. 127, 261802 (2021).
  5. J. Aalbers et al. (LZ Collaboration), First dark matter search results from the LUX-ZEPLIN (LZ) experiment, Phys. Rev. Lett. 131, 041002 (2023).
  6. Benjamin W. Lee and Steven Weinberg, Cosmological lower bound on heavy neutrino masses, Phys. Rev. Lett. 39, 165 (1977).
  7. Edward W. Kolb and Keith A. Olive, The Lee-Weinberg bound revisited, Phys. Rev. D 33, 1202 (1986); Phys. Rev. D 34, 2531(E) (1986).
  8. Gordan Krnjaic, Probing light thermal dark-matter with a Higgs portal mediator, Phys. Rev. D 94, 073009 (2016).
  9. John McDonald, Gauge singlet scalars as cold dark matter, Phys. Rev. D 50, 3637 (1994).
  10. C. P. Burgess, Maxim Pospelov, and Tonnis ter Veldhuis, The minimal model of nonbaryonic dark matter: A singlet scalar, Nucl. Phys. B619, 709 (2001).
  11. James D. Wells, How to find a hidden world at the large hadron collider, arXiv:0803.1243.
  12. H. Sieber, D. V. Kirpichnikov, I. V. Voronchikhin, P. Crivelli, S. N. Gninenko, M. M. Kirsanov, N. V. Krasnikov, L. Molina-Bueno, and S. K. Sekatskii, Probing hidden sectors with a muon beam: Implication of spin-0 dark matter mediators for the muon (g-2) anomaly and the validity of the Weiszäcker-Williams approach, Phys. Rev. D 108, 056018 (2023).
  13. Jinhui Guo, Jia Liu, Chenhao Peng, and Xiao-Ping Wang, Probing purely inelastic scalar dark matter across colliders and gravitational wave observatories, Phys. Rev. D 112, 115014 (2025).
  14. I. V. Voronchikhin and D. V. Kirpichnikov, Probing scalar, Dirac, Majorana, and vector dark matter through a spin-0 electron-specific mediator at electron fixed-target experiments, Phys. Rev. D 109, 075012 (2024).
  15. Mathias Becker, Emanuele Copello, Julia Harz, and Martin Napetschnig, Manual for SE+BSF4DM—A micrOMEGAs package for sommerfeld effect and bound state formation in colored dark sectors, arXiv:2512.02155.
  16. Mathias Becker, Emanuele Copello, Julia Harz, and Martin Napetschnig, Sommerfeld effect and bound state formation for dark matter models with colored mediators with SE+BSF4DM, arXiv:2601.03026.
  17. Zihan Wang, Scalar-mediated inelastic dark matter as a solution to Small-Scale structure anomalies, arXiv:2512.18959.
  18. Bob Holdom, Two U(1)’s and epsilon charge shifts, Phys. Lett. 166B, 196 (1986).
  19. Eder Izaguirre, Gordan Krnjaic, Philip Schuster, and Natalia Toro, Analyzing the discovery potential for light dark matter, Phys. Rev. Lett. 115, 251301 (2015).
  20. Brian Batell, Rouven Essig, and Ze’ev Surujon, Strong constraints on sub-GeV dark sectors from SLAC beam dump E137, Phys. Rev. Lett. 113, 171802 (2014).
  21. Aliaksei Kachanovich, Sergey Kovalenko, Serguei Kuleshov, Valery E. Lyubovitskij, and Alexey S. Zhevlakov, Lepton phenomenology of Stueckelberg portal to dark sector, Phys. Rev. D 105, 075004 (2022).
  22. Valery E. Lyubovitskij, Alexey S. Zhevlakov, Aliaksei Kachanovich, and Serguei Kuleshov, Dark SU(2) Stueckelberg portal, Phys. Rev. D 107, 055006 (2023).
  23. Dmitry Gorbunov and Dmitry Kalashnikov, Probing light exotics from a hidden sector at c−τ factories with polarized electron beams, Phys. Rev. D 107, 015014 (2023).
  24. Jérôme Claude, Maíra Dutra, and Stephen Godfrey, Probing feebly interacting dark matter with monojet searches, Phys. Rev. D 107, 075006 (2023).
  25. Wenyu Wang, Wu-Long Xu, Jin Min Yang, and Rui Zhu, Direct detection of cosmic ray-boosted puffy dark matter, Nucl. Phys. B995, 116348 (2023).
  26. I. V. Voronchikhin and D. V. Kirpichnikov, Implication of the Weizsacker-Williams approximation for the dark matter mediator production, Phys. Rev. D 111, 035034 (2025).
  27. R. Andrew Gustafson, Gonzalo Herrera, Mainak Mukhopadhyay, Kohta Murase, and Ian M. Shoemaker, Cosmic-ray boosted inelastic dark matter from neutrino-emitting active galactic nuclei (2025).
  28. Gonzalo Herrera, Alejandro Ibarra, and Satoshi Shirai, Enhanced prospects for direct detection of inelastic dark matter from a non-galactic diffuse component, J. Cosmol. Astropart. Phys. 04 (2023) 026.
  29. R. Andrew Gustafson, Gonzalo Herrera, Mainak Mukhopadhyay, Kohta Murase, and Ian M. Shoemaker, Cosmic-ray cooling in active galactic nuclei as a new probe of inelastic dark matter, Phys. Rev. D 111, L121303 (2025).
  30. Hyun Min Lee, Myeonghun Park, and Veronica Sanz, Gravity-mediated (or composite) dark matter, Eur. Phys. J. C 74, 2715 (2014).
  31. Yoo-Jin Kang and Hyun Min Lee, Lightening gravity-mediated dark matter, Eur. Phys. J. C 80, 602 (2020).
  32. Joshua A. Gill, Dipan Sengupta, and Anthony G. Williams, Graviton-photon production with a massive spin-2 particle, Phys. Rev. D 108, L051702 (2023).
  33. Wenyu Wang, Lei Wu, Jin Min Yang, Hang Zhou, and Bin Zhu, Cosmic ray boosted sub-GeV gravitationally interacting dark matter in direct detection, J. High Energy Phys. 12 (2020) 072; 02 (2021) 52.
  34. Arturo de Giorgi and Stefan Vogl, Warm dark matter from a gravitational freeze-in in extra dimensions, J. High Energy Phys. 04 (2023) 032.
  35. I. V. Voronchikhin and D. V. Kirpichnikov, The bremsstrahlung-like production of the massive spin-2 dark matter mediator, Eur. Phys. J. C 85, 1110 (2025).
  36. Junzhe Liu and Alfredo Gurrola, Probing freeze-in dark matter via a spin-2 portal at the LHC with vector boson fusion and machine learning, arXiv:2604.02604.
  37. David Tucker-Smith and Neal Weiner, Inelastic dark matter, Phys. Rev. D 64, 043502 (2001).
  38. R. Bernabei et al., Final model independent result of DAMA/LIBRA-phase1, Eur. Phys. J. C 73, 2648 (2013).
  39. Andrea De Simone, Veronica Sanz, and Hiromitsu Phil Sato, Pseudo-Dirac dark matter leaves a trace, Phys. Rev. Lett. 105, 121802 (2010).
  40. Masha Baryakhtar, Asher Berlin, Hongwan Liu, and Neal Weiner, Electromagnetic signals of inelastic dark matter scattering, J. High Energy Phys. 06 (2022) 047.
  41. Mariana Carrillo González and Natalia Toro, Cosmology and signals of light pseudo-Dirac dark matter, J. High Energy Phys. 04 (2022) 060.
  42. Eder Izaguirre, Yonatan Kahn, Gordan Krnjaic, and Matthew Moschella, Testing light dark matter coannihilation with fixed-target experiments, Phys. Rev. D 96, 055007 (2017).
  43. Ana Luisa Foguel, Peter Reimitz, and Renata Zukanovich Funchal, Unlocking the inelastic dark matter window with vector mediators, J. High Energy Phys. 05 (2025) 001.
  44. I. V. Voronchikhin and D. V. Kirpichnikov, Examining scalar portal inelastic dark matter with lepton fixed-target experiments, Phys. Rev. D 113, 015031 (2026).
  45. Sergei N. Gninenko, N. V. Krasnikov, I. V. Voronchikhin, and D. V. Kirpichnikov, Missing energy signatures of inelastic magnetic dipole DM at NA64e, arXiv:2603.28278.
  46. Asher Berlin and Felix Kling, Inelastic dark matter at the LHC lifetime frontier: ATLAS, CMS, LHCb, CODEX-b, FASER, and MATHUSLA, Phys. Rev. D 99, 015021 (2019).
  47. Krzysztof Jodłowski, Looking forward to inelastic DM with electromagnetic form factors at FASER and beam dump experiments, Phys. Rev. D 108, 115025 (2023).
  48. Keith R. Dienes, Jonathan L. Feng, Max Fieg, Fei Huang, Seung J. Lee, and Brooks Thomas, Extending the discovery potential for inelastic-dipole dark matter with FASER, Phys. Rev. D 107, 115006 (2023).
  49. Mark W. Goodman and Edward Witten, Detectability of certain dark matter candidates, Phys. Rev. D 31, 3059 (1985).
  50. Marc Schumann, Direct detection of WIMP dark matter: Concepts and status, J. Phys. G 46, 103003 (2019).
  51. Rouven Essig, Jeremy Mardon, and Tomer Volansky, Direct detection of sub-GeV dark matter, Phys. Rev. D 85, 076007 (2012).
  52. Rouven Essig, Aaron Manalaysay, Jeremy Mardon, Peter Sorensen, and Tomer Volansky, First direct detection limits on sub-GeV dark matter from XENON10, Phys. Rev. Lett. 109, 021301 (2012).
  53. Rouven Essig, Tomer Volansky, and Tien-Tien Yu, New constraints and prospects for sub-GeV dark matter scattering off electrons in xenon, Phys. Rev. D 96, 043017 (2017).
  54. Timon Emken, Rouven Essig, Chris Kouvaris, and Mukul Sholapurkar, Direct detection of strongly interacting Sub-GeV dark matter via electron recoils, J. Cosmol. Astropart. Phys. 09 (2019) 070.
  55. Rouven Essig, Marivi Fernandez-Serra, Jeremy Mardon, Adrian Soto, Tomer Volansky, and Tien-Tien Yu, Direct detection of sub-GeV dark matter with semiconductor targets, J. High Energy Phys. 05 (2016) 046.
  56. A. R. Caddell, V. V. Flambaum, and B. M. Roberts, Accurate electron-recoil ionization factors for dark matter direct detection in xenon, krypton, and argon, Phys. Rev. D 108, 083030 (2023).
  57. Douglas P. Finkbeiner, Tracy R. Slatyer, Neal Weiner, and Itay Yavin, PAMELA, DAMA, INTEGRAL and signatures of metastable excited WIMPs, J. Cosmol. Astropart. Phys. 09 (2009) 037.
  58. Keisuke Harigaya, Yuichiro Nakai, and Motoo Suzuki, Inelastic dark matter electron scattering and the XENON1T excess, Phys. Lett. B 809, 135729 (2020).
  59. E. Aprile et al. (XENON Collaboration), Excess electronic recoil events in XENON1T, Phys. Rev. D 102, 072004 (2020).
  60. Hong-Jian He, Yu-Chen Wang, and Jiaming Zheng, Probing light inelastic dark matter from direct detection, Phys. Dark Universe 46, 101670 (2024).
  61. Yu-Chen Wang, Youhui Yun, Hong-Jian He, and Yue Meng, Search for light inelastic dark matter with low-energy ionization signatures in PandaX-4T, arXiv:2508.13062.
  62. Nirmalya Brahma, Saniya Heeba, and Katelin Schutz, Resonant pseudo-Dirac dark matter as a sub-GeV thermal target, Phys. Rev. D 109, 035006 (2024).
  63. Asher Berlin, Nikita Blinov, Gordan Krnjaic, Philip Schuster, and Natalia Toro, Dark matter, millicharges, axion and scalar particles, gauge bosons, and other new physics with LDMX, Phys. Rev. D 99, 075001 (2019).
  64. Chien-Yi Chen, Jonathan Kozaczuk, and Yi-Ming Zhong, Exploring leptophilic dark matter with NA64-μ, J. High Energy Phys. 10 (2018) 154.
  65. Brian Batell, Ayres Freitas, Ahmed Ismail, and David Mckeen, Flavor-specific scalar mediators, Phys. Rev. D 98, 055026 (2018).
  66. Herbi K. Dreiner, Howard E. Haber, and Stephen P. Martin, Two-component spinor techniques and Feynman rules for quantum field theory and supersymmetry, Phys. Rep. 494, 1 (2010).
  67. Gordan Krnjaic, David McKeen, Riku Mizuta, Gopolang Mohlabeng, David E. Morrissey, and Douglas Tuckler, X-rays from inelastic dark matter freeze-in, Phys. Rev. D 112, 115039 (2025).
  68. Giovani Dalla Valle Garcia, A minimalistic model for inelastic dark matter, Phys. Lett. B 862, 139320 (2025).
  69. Kim Griest and David Seckel, Three exceptions in the calculation of relic abundances, Phys. Rev. D 43, 3191 (1991).
  70. Joakim Edsjo and Paolo Gondolo, Neutralino relic density including coannihilations, Phys. Rev. D 56, 1879 (1997).
  71. Gordan Krnjaic, Testing thermal-relic dark matter with a dark photon mediator, arXiv:2505.04626.
  72. Lars Husdal, On effective degrees of freedom in the early universe, Galaxies 4, 78 (2016).
  73. Mark Srednicki, Richard Watkins, and Keith A. Olive, Calculations of relic densities in the early universe, Nucl. Phys. B310, 693 (1988).
  74. Edward W. Kolb and Michael S. Turner, The Early Universe (Taylor and Francis, London, 2019), Vol. 69.
  75. Tracy R. Slatyer, Nikhil Padmanabhan, and Douglas P. Finkbeiner, CMB constraints on WIMP annihilation: Energy absorption during the recombination epoch, Phys. Rev. D 80, 043526 (2009).
  76. Asher Berlin, Gordan Krnjaic, and Elena Pinetti, Reviving MeV-GeV indirect detection with inelastic dark matter, Phys. Rev. D 110, 035015 (2024).
  77. E. Aprile et al. (XENON Collaboration), Light dark matter search with ionization signals in XENON1T, Phys. Rev. Lett. 123, 251801 (2019).
  78. Shuaijie Li et al. (PandaX Collaboration), Search for light dark matter with ionization signals in the PandaX-4T experiment, Phys. Rev. Lett. 130, 261001 (2023).
  79. D. S. Akerib et al. (LZ Collaboration), Search for new physics via low-energy electron recoils with a 4.2  tonne×year exposure from the LZ experiment, arXiv:2511.17350.
  80. Martin C. Smith et al., The RAVE survey: Constraining the local galactic escape speed, Mon. Not. R. Astron. Soc. 379, 755 (2007).
  81. Anne M Green, Astrophysical uncertainties on the local dark matter distribution and direct detection experiments, J. Phys. G 44, 084001 (2017).
  82. Gordan Krnjaic, Duncan Rocha, and Tanner Trickle, The non-relativistic effective field theory of dark matter-electron interactions, J. High Energy Phys. 03 (2025) 165.
  83. Riccardo Catena, Timon Emken, Nicola A. Spaldin, and Walter Tarantino, Atomic responses to general dark matter-electron interactions, Phys. Rev. Res. 2, 033195 (2020); 7, 019001(E) (2025).
  84. Jin-Han Liang, Yi Liao, Xiao-Dong Ma, and Hao-Lin Wang, A systematic investigation on dark matter-electron scattering in effective field theories, J. High Energy Phys. 07 (2024) 279.
  85. J. I. Read, The local dark matter density, J. Phys. G 41, 063101 (2014).
  86. Christopher Savage, Katherine Freese, and Paolo Gondolo, Annual modulation of dark matter in the presence of streams, Phys. Rev. D 74, 043531 (2006).
  87. Christopher McCabe, The astrophysical uncertainties of dark matter direct detection experiments, Phys. Rev. D 82, 023530 (2010).
  88. Difan Yi et al., Direct observation of the Migdal effect induced by neutron bombardment, Nature (London) 649, 580 (2026).
  89. Masahiro Ibe, Wakutaka Nakano, Yutaro Shoji, and Kazumine Suzuki, Migdal effect in dark matter direct detection experiments, J. High Energy Phys. 03 (2018) 194.
  90. D. Baxter et al., Recommended conventions for reporting results from direct dark matter searches, Eur. Phys. J. C 81, 907 (2021).
  91. Gabriel Magill, Ryan Plestid, Maxim Pospelov, and Yu-Dai Tsai, Dipole portal to heavy neutral leptons, Phys. Rev. D 98, 115015 (2018).
  92. Gabriel Magill, Ryan Plestid, Maxim Pospelov, and Yu-Dai Tsai, Millicharged particles in neutrino experiments, Phys. Rev. Lett. 122, 071801 (2019).
  93. S. Navas et al. (Particle Data Group Collaboration), Review of particle physics, Phys. Rev. D 110, 030001 (2024).
  94. Glen Cowan, Kyle Cranmer, Eilam Gross, and Ofer Vitells, Asymptotic formulae for likelihood-based tests of new physics, Eur. Phys. J. C 71, 1554 (2011); 73, 2501(E) (2013).
  95. P. Agnes et al. (DarkSide-50 Collaboration), Search for low mass dark matter in DarkSide-50: The Bayesian network approach, Eur. Phys. J. C 83, 322 (2023).
  96. J. P. Lees et al. (BABAR Collaboration, Search for invisible decays of a dark photon produced in e+e− collisions at BABAR, Phys. Rev. Lett. 119, 131804 (2017).
  97. Gordan Krnjaic, Gustavo Marques-Tavares, Diego Redigolo, and Kohsaku Tobioka, Probing muonphilic force carriers and dark matter at kaon factories, Phys. Rev. Lett. 124, 041802 (2020).
  98. Eduardo Cortina Gil et al. (NA62 Collaboration), Search for K+ decays to a muon and invisible particles, Phys. Lett. B 816, 136259 (2021).

Outline

Information

Phys. Rev. D 114, 055054– Published 29 September, 2026
  • Received 17 April 2026
  • Accepted 8 September 2026
Crossmark - Check for updates button
Creative Commons Logo

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.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation