A second Higgs from the Higgs portal

  • Adam Falkowski
  • Christian Gross
  • Oleg Lebedev
Open Access
Regular Article - Theoretical Physics


In the Higgs portal framework, the Higgs field generally mixes with the Standard Model (SM) singlet leading to the existence of two states, one of which is identified with the 125 GeV scalar observed at the LHC. In this work, we analyse direct and indirect constraints on the second mass eigenstate and the corresponding mixing angle. The existence of the additional scalar can be beneficial as it can stabilise the otherwise-metastable electroweak vacuum. We find parameter regions where all of the bounds, including the stability constraints, are satisfied. We also study prospects for observing the decay of the heavier state into a pair of the 125 GeV Higgs-like scalars.


Higgs Physics Beyond Standard Model 


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]
    V. Silveira and A. Zee, SCALAR PHANTOMS, Phys. Lett. B 161 (1985) 136 [INSPIRE].ADSCrossRefGoogle Scholar
  2. [2]
    R. Schabinger and J.D. Wells, A Minimal spontaneously broken hidden sector and its impact on Higgs boson physics at the large hadron collider, Phys. Rev. D 72 (2005) 093007 [hep-ph/0509209] [INSPIRE].ADSGoogle Scholar
  3. [3]
    B. Patt and F. Wilczek, Higgs-field portal into hidden sectors, hep-ph/0605188 [INSPIRE].
  4. [4]
    D. O’Connell, M.J. Ramsey-Musolf and M.B. Wise, Minimal Extension of the Standard Model Scalar Sector, Phys. Rev. D 75 (2007) 037701 [hep-ph/0611014] [INSPIRE].ADSGoogle Scholar
  5. [5]
    V. Barger, P. Langacker, M. McCaskey, M.J. Ramsey-Musolf and G. Shaughnessy, LHC Phenomenology of an Extended Standard Model with a Real Scalar Singlet, Phys. Rev. D 77 (2008) 035005 [arXiv:0706.4311] [INSPIRE].ADSGoogle Scholar
  6. [6]
    D. Bertolini and M. McCullough, The Social Higgs, JHEP 12 (2012) 118 [arXiv:1207.4209] [INSPIRE].ADSCrossRefGoogle Scholar
  7. [7]
    C. Englert, J. Jaeckel, V.V. Khoze and M. Spannowsky, Emergence of the Electroweak Scale through the Higgs Portal, JHEP 04 (2013) 060 [arXiv:1301.4224] [INSPIRE].ADSCrossRefGoogle Scholar
  8. [8]
    E. Gabrielli et al., Towards Completing the Standard Model: Vacuum Stability, EWSB and Dark Matter, Phys. Rev. D 89 (2014) 015017 [arXiv:1309.6632] [INSPIRE].ADSGoogle Scholar
  9. [9]
    D. Buttazzo et al., Investigating the near-criticality of the Higgs boson, JHEP 12 (2013) 089 [arXiv:1307.3536] [INSPIRE].ADSCrossRefGoogle Scholar
  10. [10]
    F. Bezrukov, M.Y. Kalmykov, B.A. Kniehl and M. Shaposhnikov, Higgs Boson Mass and New Physics, JHEP 10 (2012) 140 [arXiv:1205.2893] [INSPIRE].ADSCrossRefGoogle Scholar
  11. [11]
    S. Alekhin, A. Djouadi and S. Moch, The top quark and Higgs boson masses and the stability of the electroweak vacuum, Phys. Lett. B 716 (2012) 214 [arXiv:1207.0980] [INSPIRE].ADSCrossRefGoogle Scholar
  12. [12]
    O. Lebedev and A. Westphal, Metastable Electroweak Vacuum: Implications for Inflation, Phys. Lett. B 719 (2013) 415 [arXiv:1210.6987] [INSPIRE].ADSCrossRefGoogle Scholar
  13. [13]
    O. Lebedev, On Stability of the Electroweak Vacuum and the Higgs Portal, Eur. Phys. J. C 72 (2012) 2058 [arXiv:1203.0156] [INSPIRE].ADSCrossRefGoogle Scholar
  14. [14]
    J. Elias-Miro, J.R. Espinosa, G.F. Giudice, H.M. Lee and A. Strumia, Stabilization of the Electroweak Vacuum by a Scalar Threshold Effect, JHEP 06 (2012) 031 [arXiv:1203.0237] [INSPIRE].ADSCrossRefGoogle Scholar
  15. [15]
    G.M. Pruna and T. Robens, Higgs singlet extension parameter space in the light of the LHC discovery, Phys. Rev. D 88 (2013) 115012 [arXiv:1303.1150] [INSPIRE].ADSGoogle Scholar
  16. [16]
    D. Lopez-Val and T. Robens, Δr and the W-boson mass in the singlet extension of the standard model, Phys. Rev. D 90 (2014) 114018 [arXiv:1406.1043] [INSPIRE].ADSGoogle Scholar
  17. [17]
    T. Robens and T. Stefaniak, Status of the Higgs Singlet Extension of the Standard Model after LHC Run 1, Eur. Phys. J. C 75 (2015) 104 [arXiv:1501.02234] [INSPIRE].ADSCrossRefGoogle Scholar
  18. [18]
    S. Profumo, M.J. Ramsey-Musolf, C.L. Wainwright and P. Winslow, Singlet-catalyzed electroweak phase transitions and precision Higgs boson studies, Phys. Rev. D 91 (2015) 035018 [arXiv:1407.5342] [INSPIRE].ADSGoogle Scholar
  19. [19]
    C.-Y. Chen, S. Dawson and I.M. Lewis, Exploring resonant di-Higgs boson production in the Higgs singlet model, Phys. Rev. D 91 (2015) 035015 [arXiv:1410.5488] [INSPIRE].ADSGoogle Scholar
  20. [20]
    V. Martin-Lozano, J.M. Moreno and C.B. Park, Resonant Higgs boson pair production in the \( hh\to b\overline{b}WW\to b\overline{b}{\ell}^{+}\nu {\ell}^{-}\overline{\nu} \) decay channel, arXiv:1501.03799 [INSPIRE].
  21. [21]
    C. Englert, T. Plehn, D. Zerwas and P.M. Zerwas, Exploring the Higgs portal, Phys. Lett. B 703 (2011) 298 [arXiv:1106.3097] [INSPIRE].ADSCrossRefGoogle Scholar
  22. [22]
    C. Englert, M. Spannowsky and C. Wymant, Partially (in)visible Higgs decays at the LHC, Phys. Lett. B 718 (2012) 538 [arXiv:1209.0494] [INSPIRE].ADSCrossRefGoogle Scholar
  23. [23]
    J.M. No and M. Ramsey-Musolf, Probing the Higgs Portal at the LHC Through Resonant di-Higgs Production, Phys. Rev. D 89 (2014) 095031 [arXiv:1310.6035] [INSPIRE].ADSGoogle Scholar
  24. [24]
    O. Lebedev and H.M. Lee, Higgs Portal Inflation, Eur. Phys. J. C 71 (2011) 1821 [arXiv:1105.2284] [INSPIRE].ADSCrossRefGoogle Scholar
  25. [25]
    M. Gonderinger, H. Lim and M.J. Ramsey-Musolf, Complex Scalar Singlet Dark Matter: Vacuum Stability and Phenomenology, Phys. Rev. D 86 (2012) 043511 [arXiv:1202.1316] [INSPIRE].ADSGoogle Scholar
  26. [26]
    V.V. Khoze, C. McCabe and G. Ro, Higgs vacuum stability from the dark matter portal, JHEP 08 (2014) 026 [arXiv:1403.4953] [INSPIRE].ADSCrossRefGoogle Scholar
  27. [27]
    S. Moch, Precision determination of the top-quark mass, PoS(LL2014)054 [arXiv:1408.6080] [INSPIRE].
  28. [28]
    ALEPH, DELPHI, L3, OPAL, SLD, LEP Electroweak Working Group, SLD Electroweak Group, SLD Heavy Flavour Group collaboration, S. Schael et al., Precision electroweak measurements on the Z resonance, Phys. Rept. 427 (2006) 257 [hep-ex/0509008] [INSPIRE].
  29. [29]
    CDF, D0 collaboration, T.E.W. Group, 2012 Update of the Combination of CDF and D0 Results for the Mass of the W Boson, arXiv:1204.0042 [INSPIRE].
  30. [30]
    Particle Data Group collaboration, J. Beringer et al., Review of Particle Physics (RPP), Phys. Rev. D 86 (2012) 010001 [INSPIRE].
  31. [31]
    ALEPH, DELPHI, L3, OPAL, LEP Electroweak collaboration, S. Schael et al., Electroweak Measurements in Electron-Positron Collisions at W-Boson-Pair Energies at LEP, Phys. Rept. 532 (2013) 119 [arXiv:1302.3415] [INSPIRE].
  32. [32]
    Gfitter Group collaboration, M. Baak et al., The global electroweak fit at NNLO and prospects for the LHC and ILC, Eur. Phys. J. C 74 (2014) 3046 [arXiv:1407.3792] [INSPIRE].
  33. [33]
    J.D. Wells, TASI lecture notes: Introduction to precision electroweak analysis, hep-ph/0512342 [INSPIRE].
  34. [34]
    ATLAS collaboration, Measurement of Higgs boson production in the diphoton decay channel in pp collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector, Phys. Rev. D 90 (2014) 112015 [arXiv:1408.7084] [INSPIRE].
  35. [35]
    ATLAS collaboration, Search for Scalar Diphoton Resonances in the Mass Range 65 − 600 GeV with the ATLAS Detector in pp Collision Data at \( \sqrt{s}=8 \) TeV, Phys. Rev. Lett. 113 (2014)171801 [arXiv:1407.6583] [INSPIRE].
  36. [36]
    CMS collaboration, Observation of the diphoton decay of the Higgs boson and measurement of its properties, Eur. Phys. J. C 74 (2014) 3076 [arXiv:1407.0558] [INSPIRE].
  37. [37]
    ATLAS collaboration, Measurements of Higgs boson production and couplings in the four-lepton channel in pp collisions at center-of-mass energies of 7 and 8 TeV with the ATLAS detector, Phys. Rev. D 91 (2015) 012006 [arXiv:1408.5191] [INSPIRE].
  38. [38]
    CMS collaboration, Precise determination of the mass of the Higgs boson and tests of compatibility of its couplings with the standard model predictions using proton collisions at 7 and 8 TeV, arXiv:1412.8662 [INSPIRE].
  39. [39]
    LHC Higgs Cross Section Working Group collaboration, S. Dittmaier et al., Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables, arXiv:1101.0593 [INSPIRE].
  40. [40]
    CMS collaboration, Measurement of the properties of a Higgs boson in the four-lepton final state, Phys. Rev. D 89 (2014) 092007 [arXiv:1312.5353] [INSPIRE].ADSGoogle Scholar
  41. [41]
    ATLAS collaboration, Search for a high-mass Higgs boson in the HWWlνlν decay channel with the ATLAS detector using 21 fb −1 of proton-proton collision data, ATLAS-CONF-2013-067 (2013).
  42. [42]
    CMS collaboration, Search for resonant HH production in 2gamma+2b channel, CMS-PAS-HIG-13-032 (Search for resonant HH production in 2gamma+2b channel).
  43. [43]
    CMS collaboration, Search for di-Higgs resonances decaying to 4 bottom quarks, CMS-PAS-HIG-14-013 (Search for di-Higgs resonances decaying to 4 bottom quarks).
  44. [44]
    ATLAS collaboration, Search For Higgs Boson Pair Production in the \( \gamma \gamma b\overline{b} \) Final State using pp Collision Data at \( \sqrt{s}=8 \) TeV from the ATLAS Detector, Phys. Rev. Lett. 114 (2015)081802 [arXiv:1406.5053] [INSPIRE].
  45. [45]
    LEP Working Group for Higgs boson searches, ALEPH, DELPHI, L3, OPAL collaboration, R. Barate et al., Search for the standard model Higgs boson at LEP, Phys. Lett. B 565 (2003) 61 [hep-ex/0306033] [INSPIRE].
  46. [46]
    DELPHI collaboration, P. Abreu et al., Search for low mass Higgs bosons produced in Z0 decays, Z. Phys. C 51 (1991) 25 [INSPIRE].
  47. [47]
    LHCb collaboration, Differential branching fraction and angular analysis of the B +K + μ + μ decay, JHEP 02 (2013) 105 [arXiv:1209.4284] [INSPIRE].
  48. [48]
    Belle collaboration, J.-T. Wei et al., Measurement of the Differential Branching Fraction and Forward-Backword Asymmetry for BK * + , Phys. Rev. Lett. 103 (2009) 171801 [arXiv:0904.0770] [INSPIRE].
  49. [49]
    BaBar collaboration, J.P. Lees et al., Search for di-muon decays of a low-mass Higgs boson in radiative decays of the Γ(1S), Phys. Rev. D 87 (2013) 031102 [arXiv:1210.0287] [INSPIRE].
  50. [50]
    K. Schmidt-Hoberg, F. Staub and M.W. Winkler, Constraints on light mediators: confronting dark matter searches with B physics, Phys. Lett. B 727 (2013) 506 [arXiv:1310.6752] [INSPIRE].ADSCrossRefGoogle Scholar
  51. [51]
    M. Heikinheimo, A. Racioppi, M. Raidal and C. Spethmann, Twin Peak Higgs, Phys. Lett. B 726 (2013) 781 [arXiv:1307.7146] [INSPIRE].ADSCrossRefGoogle Scholar

Copyright information

© The Author(s) 2015

Authors and Affiliations

  1. 1.Laboratoire de Physique Théorique, CNRS - UMR 8627, Université de Paris-Sud 11Orsay CedexFrance
  2. 2.Department of Physics and Helsinki Institute of PhysicsHelsinkiFinland

Personalised recommendations