Search for a heavy dark photon at future e+e colliders

  • Min He
  • Xiao-Gang He
  • Cheng-Kai Huang
  • Gang Li
Open Access
Regular Article - Experimental Physics


A coupling of a dark photon A from a U(1)A′ with the standard model (SM) particles can be generated through kinetic mixing represented by a parameter ϵ. A non-zero ϵ also induces a mixing between A and Z if dark photon mass mA′ is not zero. This mixing can be large when mA′ is close to mZ even if the parameter ϵ is small. Many efforts have been made to constrain the parameter ϵ for a low dark photon mass mA′ compared with the Z boson mass mZ . We study the search for dark photon in e+e → γA → γμ+μ for a dark photon mass mA′ as large as kinematically allowed at future e+e colliders. For large mA′, care should be taken to properly treat possible large mixing between A and Z. We obtain sensitivities to the parameter ϵ for a wide range of dark photon mass at planed e+ e colliders, such as Circular Electron Positron Collider (CEPC), International Linear Collider (ILC) and Future Circular Collider (FCC-ee). For the dark photon mass 20 GeV ≲ mA′ ≲ 330 GeV, the 2σ exclusion limits on the mixing parameter are ϵ ≲ 10−3-10−2. The CEPC with \( \sqrt{s}=240 \) GeV and FCC-ee with \( \sqrt{s}=160 \) GeV are more sensitive than the constraint from current LHCb measurement once the dark photon mass mA′ ≳ 50 GeV. For mA′ ≳ 220 GeV, the sensitivity at the FCC-ee with \( \sqrt{s}=350 \) GeV and 1.5 ab−1 is better than that at the 13 TeV LHC with 300 fb−1, while the sensitivity at the CEPC with \( \sqrt{s}=240 \) GeV and 5ab−1 can be even better than that at 13TeV LHC with 3ab−1 for mA′ ≳ 180 GeV. We also comment on sensitivities of e+e → γA with dark photon decay into several other channels at future e+e colliders.


Beyond Standard Model e+-e- Experiments 


Open Access

This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.


  1. [1]
    L.B. Okun, Limits of electrodynamics: paraphotons?, Sov. Phys. JETP 56 (1982) 502 [INSPIRE].Google Scholar
  2. [2]
    B. Holdom, Two U(1)’s and Epsilon Charge Shifts, Phys. Lett. B 166 (1986) 196 [INSPIRE].
  3. [3]
    R. Foot and X.-G. He, Comment on Z Z-prime mixing in extended gauge theories, Phys. Lett. B 267 (1991) 509 [INSPIRE].
  4. [4]
    R. Foot, X.G. He, H. Lew and R.R. Volkas, Model for a light Z-prime boson, Phys. Rev. D 50 (1994) 4571 [hep-ph/9401250] [INSPIRE].
  5. [5]
    R. Foot and R.R. Volkas, Neutrino physics and the mirror world: How exact parity symmetry explains the solar neutrino deficit, the atmospheric neutrino anomaly and the LSND experiment, Phys. Rev. D 52 (1995) 6595 [hep-ph/9505359] [INSPIRE].
  6. [6]
    M. Pospelov, A. Ritz and M.B. Voloshin, Secluded WIMP Dark Matter, Phys. Lett. B 662 (2008) 53 [arXiv:0711.4866] [INSPIRE].
  7. [7]
    N. Arkani-Hamed, D.P. Finkbeiner, T.R. Slatyer and N. Weiner, A Theory of Dark Matter, Phys. Rev. D 79 (2009) 015014 [arXiv:0810.0713] [INSPIRE].
  8. [8]
    J. Erler, P. Langacker, S. Munir and E. Rojas, Improved Constraints on Z-prime Bosons from Electroweak Precision Data, JHEP 08 (2009) 017 [arXiv:0906.2435] [INSPIRE].ADSCrossRefGoogle Scholar
  9. [9]
    C.-R. Chen, F. Takahashi and T.T. Yanagida, Gamma rays and positrons from a decaying hidden gauge boson, Phys. Lett. B 671 (2009) 71 [arXiv:0809.0792] [INSPIRE].
  10. [10]
    K. Petraki and R.R. Volkas, Review of asymmetric dark matter, Int. J. Mod. Phys. A 28 (2013) 1330028 [arXiv:1305.4939] [INSPIRE].
  11. [11]
    R. Foot and S. Vagnozzi, Solving the small-scale structure puzzles with dissipative dark matter, JCAP 07 (2016) 013 [arXiv:1602.02467] [INSPIRE].ADSCrossRefGoogle Scholar
  12. [12]
    P.-H. Gu and X.-G. He, Realistic model for a fifth force explaining anomaly in 8 Be 8 Be e + e Decay, Nucl. Phys. B 919 (2017) 209 [arXiv:1606.05171] [INSPIRE].
  13. [13]
    C.-F. Chang, Hidden Photon Compton and Bremsstrahlung in White Dwarf Anomalous Cooling and Luminosity Functions, arXiv:1607.03347 [INSPIRE].
  14. [14]
    M. Cirelli, P. Panci, K. Petraki, F. Sala and M. Taoso, Dark Matter’s secret liaisons: phenomenology of a dark U(1) sector with bound states, JCAP 05 (2017) 036 [arXiv:1612.07295] [INSPIRE].ADSCrossRefGoogle Scholar
  15. [15]
    J.D. Bjorken, R. Essig, P. Schuster and N. Toro, New Fixed-Target Experiments to Search for Dark Gauge Forces, Phys. Rev. D 80 (2009) 075018 [arXiv:0906.0580] [INSPIRE].
  16. [16]
    H. Davoudiasl, H.-S. Lee and W.J. Marciano, Muon Anomaly and Dark Parity Violation, Phys. Rev. Lett. 109 (2012) 031802 [arXiv:1205.2709] [INSPIRE].
  17. [17]
    SHiP collaboration, M. Anelli et al., A facility to Search for Hidden Particles (SHiP) at the CERN SPS, arXiv:1504.04956 [INSPIRE].
  18. [18]
    P. Ilten, Y. Soreq, J. Thaler, M. Williams and W. Xue, Proposed Inclusive Dark Photon Search at LHCb, Phys. Rev. Lett. 116 (2016) 251803 [arXiv:1603.08926] [INSPIRE].ADSCrossRefGoogle Scholar
  19. [19]
    LHCb collaboration, Search for Dark Photons Produced in 13 TeV pp Collisions, Phys. Rev. Lett. 120 (2018) 061801 [arXiv:1710.02867] [INSPIRE].
  20. [20]
    N. Blinov, E. Izaguirre and B. Shuve, Rare Z Boson Decays to a Hidden Sector, Phys. Rev. D 97 (2018) 015009 [arXiv:1710.07635] [INSPIRE].
  21. [21]
  22. [22]
    M. He, X.-G. He and C.-K. Huang, Dark Photon Search at A Circular e + e Collider, Int. J. Mod. Phys. A 32 (2017) 1750138 [arXiv:1701.08614] [INSPIRE].
  23. [23]
    BaBar collaboration, J.P. Lees et al., Search for a Dark Photon in e + e Collisions at BaBar, Phys. Rev. Lett. 113 (2014) 201801 [arXiv:1406.2980] [INSPIRE].
  24. [24]
    J. Liu, X.-P. Wang and F. Yu, A Tale of Two Portals: Testing Light, Hidden New Physics at Future e + e Colliders, JHEP 06 (2017) 077 [arXiv:1704.00730] [INSPIRE].
  25. [25]
    M. Karliner, M. Low, J.L. Rosner and L.-T. Wang, Radiative return capabilities of a high-energy, high-luminosity e + e collider, Phys. Rev. D 92 (2015) 035010 [arXiv:1503.07209] [INSPIRE].
  26. [26]
    ATLAS collaboration, Search for new high-mass phenomena in the dilepton final state using 36 fb −1 of proton-proton collision data at \( \sqrt{s}=13 \) TeV with the ATLAS detector, JHEP 10 (2017) 182 [arXiv:1707.02424] [INSPIRE].
  27. [27]
    F.A. Berends, G.J.H. Burgers and W.L. van Neerven, QED Radiative Corrections to the Reaction e + e , Phys. Lett. B 177 (1986) 191 [INSPIRE].
  28. [28]
    V. Barger, P. Langacker and H.-S. Lee, Six-lepton Z-prime resonance at the LHC, Phys. Rev. Lett. 103 (2009) 251802 [arXiv:0909.2641] [INSPIRE].ADSCrossRefGoogle Scholar
  29. [29]
    G. Altarelli, B. Mele and M. Ruiz-Altaba, Searching for New Heavy Vector Bosons in pp Colliders, Z. Phys. C 45 (1989) 109 [Erratum ibid. C 47 (1990) 676] [INSPIRE].
  30. [30]
    D. Curtin, R. Essig, S. Gori and J. Shelton, Illuminating Dark Photons with High-Energy Colliders, JHEP 02 (2015) 157 [arXiv:1412.0018] [INSPIRE].ADSCrossRefGoogle Scholar
  31. [31]
    CEPC-SPPC Study Group, CEPC-SPPC Preliminary Conceptual Design Report. 1. Physics and Detector, [] [INSPIRE].
  32. [32]
    TLEP Design Study Working Group collaboration, M. Bicer et al., First Look at the Physics Case of TLEP, JHEP 01 (2014) 164 [arXiv:1308.6176] [INSPIRE].
  33. [33]
    A. Blondel, P. Janot, K. Oide, D. Shatilov and F. Zimmermann, FCC-ee parameter update, in FCC-ee polarization workshop,
  34. [34]
    H. Baer et al., The International Linear Collider Technical Design Report — Volume 2: Physics, arXiv:1306.6352 [INSPIRE].
  35. [35]
    T. Barklow et al., ILC Operating Scenarios, arXiv:1506.07830 [INSPIRE].
  36. [36]
    K. Fujii et al., Physics Case for the 250 GeV Stage of the International Linear Collider, arXiv:1710.07621 [INSPIRE].
  37. [37]
    J. Alwall et al., The automated computation of tree-level and next-to-leading order differential cross sections and their matching to parton shower simulations, JHEP 07 (2014)079 [arXiv:1405.0301] [INSPIRE].
  38. [38]
    T. Sjöstrand, S. Mrenna and P.Z. Skands, PYTHIA 6.4 Physics and Manual, JHEP 05 (2006) 026 [hep-ph/0603175] [INSPIRE].
  39. [39]
    DELPHES 3 collaboration, J. de Favereau et al., DELPHES 3, A modular framework for fast simulation of a generic collider experiment, JHEP 02 (2014) 057 [arXiv:1307.6346] [INSPIRE].
  40. [40]
    D. Yu, M. Ruan, V. Boudry and H. Videau, Lepton identification at particle flow oriented detector for the future e + e Higgs factories, Eur. Phys. J. C 77 (2017) 591 [arXiv:1701.07542] [INSPIRE].
  41. [41]
    Z. Chen et al., Cross Section and Higgs Mass Measurement with Higgsstrahlung at the CEPC, Chin. Phys. C 41 (2017) 023003 [arXiv:1601.05352] [INSPIRE].
  42. [42]
    O. Cerri, M. de Gruttola, M. Pierini, A. Podo and G. Rolandi, Study the effect of beam energy spread and detector resolution on the search for Higgs boson decays to invisible particles at a future e + e circular collider, Eur. Phys. J. C 77 (2017) 116 [arXiv:1605.00100] [INSPIRE].
  43. [43]
    Linear Collider ILD Concept Group collaboration, T. Abe et al., The International Large Detector: Letter of Intent, arXiv:1006.3396 [INSPIRE].
  44. [44]
    M.-S. Chen and P.M. Zerwas, Equivalent-Particle Approximations in electron and Photon Processes of Higher Order QED, Phys. Rev. D 12 (1975) 187 [INSPIRE].
  45. [45]
    I. Hoenig, G. Samach and D. Tucker-Smith, Searching for dilepton resonances below the Z mass at the LHC, Phys. Rev. D 90 (2014) 075016 [arXiv:1408.1075] [INSPIRE].
  46. [46]
    CMS collaboration, Measurement of the differential and double-differential Drell-Yan cross sections in proton-proton collisions at \( \sqrt{s}=7 \) TeV, JHEP 12 (2013) 030 [arXiv:1310.7291] [INSPIRE].
  47. [47]
    J.M. Cline, G. Dupuis, Z. Liu and W. Xue, The windows for kinetically mixed Z’-mediated dark matter and the galactic center gamma ray excess, JHEP 08 (2014) 131 [arXiv:1405.7691] [INSPIRE].ADSCrossRefGoogle Scholar
  48. [48]
    ATLAS collaboration, Search for high-mass dilepton resonances in 20 f b −1 of pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS experiment, ATLAS-CONF-2013-017 (2013).
  49. [49]
    ATLAS collaboration, Search for high-mass dilepton resonances in pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, Phys. Rev. D 90 (2014)052005 [arXiv:1405.4123] [INSPIRE].
  50. [50]
    B. Fuks and R. Ruiz, A comprehensive framework for studying W and Z bosons at hadron colliders with automated jet veto resummation, JHEP 05 (2017) 032 [arXiv:1701.05263] [INSPIRE].
  51. [51]
    A. Hook, E. Izaguirre and J.G. Wacker, Model Independent Bounds on Kinetic Mixing, Adv. High Energy Phys. 2011 (2011) 859762 [arXiv:1006.0973] [INSPIRE].MathSciNetCrossRefzbMATHGoogle Scholar
  52. [52]
    J. Liu, L.-T. Wang, X.-P. Wang and W. Xue, Exposing Dark Sector with Future Z-Factories, arXiv:1712.07237 [INSPIRE].
  53. [53]
    I. Chakraborty, S. Mondal and B. Mukhopadhyaya, Lepton flavor violating Higgs boson decay at e + e colliders, Phys. Rev. D 96 (2017) 115020 [arXiv:1709.08112] [INSPIRE].

Copyright information

© The Author(s) 2018

Authors and Affiliations

  • Min He
    • 1
  • Xiao-Gang He
    • 1
    • 2
    • 3
  • Cheng-Kai Huang
    • 2
  • Gang Li
    • 2
  1. 1.T-D. Lee Institute and School of Physics and AstronomyShanghai Jiao Tong UniversityShanghaiChina
  2. 2.Department of PhysicsNational Taiwan UniversityTaipeiR.O.C.
  3. 3.National Center for Theoretical SciencesHsinchuR.O.C.

Personalised recommendations