An almost elementary Higgs: theory and practice

  • Daniele BarducciEmail author
  • Stefania De Curtis
  • Michele Redi
  • Andrea Tesi
Open Access
Regular Article - Theoretical Physics


We study models that interpolate between an elementary and a composite Higgs boson. Such models, arising in theories with new vector-like fermions with electroweak quantum numbers and charged under a confining gauge interaction, are entirely compatible with current data, with only weak bounds from flavor, CP-violation and precision tests. After classifying the models from the point of view of symmetries, we study their collider phenomenology at LHC. In the most relevant scenarios, bounds from present searches exclude heavy scalar isospin triplets and quintuplets up to ∼ 200 GeV and we show how dedicated searches of simple signals such as pp → 3γW could improve the reach by at least a factor of 2 with present data, reaching O(1 TeV) with higher integrated luminosities. States that mix with the SM Higgs can be tested in a variety of final states, such as 2b2γ searches relevant for double Higgs production.


Beyond Standard Model Higgs Physics Technicolor and Composite Models 


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]
    C. Kilic, T. Okui and R. Sundrum, Vectorlike Confinement at the LHC, JHEP 02 (2010) 018 [arXiv:0906.0577] [INSPIRE].ADSCrossRefzbMATHGoogle Scholar
  2. [2]
    O. Antipin and M. Redi, The Half-composite Two Higgs Doublet Model and the Relaxion, JHEP 12 (2015) 031 [arXiv:1508.01112] [INSPIRE].ADSGoogle Scholar
  3. [3]
    A. Agugliaro, O. Antipin, D. Becciolini, S. De Curtis and M. Redi, UV complete composite Higgs models, Phys. Rev. D 95 (2017) 035019 [arXiv:1609.07122] [INSPIRE].ADSGoogle Scholar
  4. [4]
    G. Panico and A. Wulzer, The Composite Nambu-Goldstone Higgs, Lect. Notes Phys. 913 (2016) 1 [arXiv:1506.01961] [INSPIRE].CrossRefzbMATHGoogle Scholar
  5. [5]
    O. Antipin, M. Redi, A. Strumia and E. Vigiani, Accidental Composite Dark Matter, JHEP 07 (2015) 039 [arXiv:1503.08749] [INSPIRE].ADSCrossRefGoogle Scholar
  6. [6]
    B. Batell, M.A. Fedderke and L.-T. Wang, Relaxation of the Composite Higgs Little Hierarchy, JHEP 12 (2017) 139 [arXiv:1705.09666] [INSPIRE].ADSCrossRefGoogle Scholar
  7. [7]
    P.W. Graham, D.E. Kaplan and S. Rajendran, Cosmological Relaxation of the Electroweak Scale, Phys. Rev. Lett. 115 (2015) 221801 [arXiv:1504.07551] [INSPIRE].ADSCrossRefGoogle Scholar
  8. [8]
    A. Mitridate, M. Redi, J. Smirnov and A. Strumia, Dark Matter as a weakly coupled Dark Baryon, JHEP 10 (2017) 210 [arXiv:1707.05380] [INSPIRE].ADSCrossRefzbMATHGoogle Scholar
  9. [9]
    G. Elor, H. Liu, T.R. Slatyer and Y. Soreq, Complementarity for Dark Sector Bound States, arXiv:1801.07723 [INSPIRE].
  10. [10]
    J. Mrazek, A. Pomarol, R. Rattazzi, M. Redi, J. Serra and A. Wulzer, The Other Natural Two Higgs Doublet Model, Nucl. Phys. B 853 (2011) 1 [arXiv:1105.5403] [INSPIRE].ADSCrossRefzbMATHGoogle Scholar
  11. [11]
    G.F. Giudice, C. Grojean, A. Pomarol and R. Rattazzi, The Strongly-Interacting Light Higgs, JHEP 06 (2007) 045 [hep-ph/0703164] [INSPIRE].
  12. [12]
    G.C. Branco, P.M. Ferreira, L. Lavoura, M.N. Rebelo, M. Sher and J.P. Silva, Theory and phenomenology of two-Higgs-doublet models, Phys. Rept. 516 (2012) 1 [arXiv:1106.0034] [INSPIRE].ADSCrossRefGoogle Scholar
  13. [13]
    R. Barbieri, A. Pomarol, R. Rattazzi and A. Strumia, Electroweak symmetry breaking after LEP-1 and LEP-2, Nucl. Phys. B 703 (2004) 127 [hep-ph/0405040] [INSPIRE].
  14. [14]
    M. Farina, G. Panico, D. Pappadopulo, J.T. Ruderman, R. Torre and A. Wulzer, Energy helps accuracy: electroweak precision tests at hadron colliders, Phys. Lett. B 772 (2017) 210 [arXiv:1609.08157] [INSPIRE].ADSCrossRefGoogle Scholar
  15. [15]
    M. Baak et al., The Electroweak Fit of the Standard Model after the Discovery of a New Boson at the LHC, Eur. Phys. J. C 72 (2012) 2205 [arXiv:1209.2716] [INSPIRE].ADSCrossRefGoogle Scholar
  16. [16]
    G. D’Ambrosio, G.F. Giudice, G. Isidori and A. Strumia, Minimal flavor violation: An Effective field theory approach, Nucl. Phys. B 645 (2002) 155 [hep-ph/0207036] [INSPIRE].
  17. [17]
    T. Enomoto and R. Watanabe, Flavor constraints on the Two Higgs Doublet Models of Z 2 symmetric and aligned types, JHEP 05 (2016) 002 [arXiv:1511.05066] [INSPIRE].ADSCrossRefGoogle Scholar
  18. [18]
    T. Alanne, D. Buarque Franzosi, M.T. Frandsen, M.L.A. Kristensen, A. Meroni and M. Rosenlyst, Partially composite Higgs models: Phenomenology and RG analysis, JHEP 01 (2018) 051 [arXiv:1711.10410] [INSPIRE].ADSCrossRefzbMATHGoogle Scholar
  19. [19]
    ACME collaboration, J. Baron et al., Order of Magnitude Smaller Limit on the Electric Dipole Moment of the Electron, Science 343 (2014) 269 [arXiv:1310.7534] [INSPIRE].
  20. [20]
    C. Kilic and T. Okui, The LHC Phenomenology of Vectorlike Confinement, JHEP 04 (2010) 128 [arXiv:1001.4526] [INSPIRE].ADSCrossRefzbMATHGoogle Scholar
  21. [21]
    A. Mariotti, D. Redigolo, F. Sala and K. Tobioka, New LHC bound on low-mass diphoton resonances, arXiv:1710.01743 [INSPIRE].
  22. [22]
    M. Cirelli, N. Fornengo and A. Strumia, Minimal dark matter, Nucl. Phys. B 753 (2006) 178 [hep-ph/0512090] [INSPIRE].
  23. [23]
    CMS collaboration, Search for a new scalar resonance decaying to a pair of Z bosons in proton-proton collisions at \( \sqrt{s}=13 \) TeV, JHEP 06 (2018) 127 [arXiv:1804.01939] [INSPIRE].
  24. [24]
    ATLAS collaboration, Search for heavy ZZ resonances in the ℓ + + and \( {\ell}^{+}{\ell}^{-}\nu \overline{\nu} \) final states using proton-proton collisions at \( \sqrt{s}=13 \) TeV with the ATLAS detector, Eur. Phys. J. C 78 (2018) 293 [arXiv:1712.06386] [INSPIRE].
  25. [25]
    ATLAS collaboration, Search for new phenomena in events with at least three photons collected in pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, Eur. Phys. J. C 76 (2016) 210 [arXiv:1509.05051] [INSPIRE].
  26. [26]
    A. Alloul, N.D. Christensen, C. Degrande, C. Duhr and B. Fuks, FeynRules 2.0A complete toolbox for tree-level phenomenology, Comput. Phys. Commun. 185 (2014) 2250 [arXiv:1310.1921] [INSPIRE].
  27. [27]
    C. Degrande, C. Duhr, B. Fuks, D. Grellscheid, O. Mattelaer and T. Reiter, UFOThe Universal FeynRules Output, Comput. Phys. Commun. 183 (2012) 1201 [arXiv:1108.2040] [INSPIRE].ADSCrossRefGoogle Scholar
  28. [28]
    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].ADSCrossRefGoogle Scholar
  29. [29]
    T. Sjöstrand, S. Mrenna and P.Z. Skands, A Brief Introduction to PYTHIA 8.1, Comput. Phys. Commun. 178 (2008) 852 [arXiv:0710.3820] [INSPIRE].
  30. [30]
    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].
  31. [31]
    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].
  32. [32]
    CMS collaboration, Search for heavy stable charged particles with 12.9 fb−1 of 2016 data, CMS-PAS-EXO-16-036 (2018).
  33. [33]
    B. Gripaios, A. Pomarol, F. Riva and J. Serra, Beyond the Minimal Composite Higgs Model, JHEP 04 (2009) 070 [arXiv:0902.1483] [INSPIRE].ADSCrossRefGoogle Scholar
  34. [34]
    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].
  35. [35]
    CMS collaboration, Search for two Higgs bosons in final states containing two photons and two bottom quarks in proton-proton collisions at 8 TeV, Phys. Rev. D 94 (2016) 052012 [arXiv:1603.06896] [INSPIRE].
  36. [36]
    ATLAS collaboration, Search for Higgs boson pair production in the \( b\overline{b}\gamma \gamma \) final state using pp collision data at \( \sqrt{s}=13 \) TeV with the ATLAS detector, ATLAS-CONF-2016-004 (2016).
  37. [37]
    CMS collaboration, Search for Higgs boson pair production in the final state containing two photons and two bottom quarks in proton-proton collisions at \( \sqrt{s}=13 \) TeV, CMS-PAS-HIG-17-008 (2017).
  38. [38]
    ATLAS collaboration, Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced in 36 fb −1 of pp collisions at \( \sqrt{s}=13 \) TeV with the ATLAS detector, JHEP 01 (2018) 055 [arXiv:1709.07242] [INSPIRE].
  39. [39]
    CMS collaboration, Search for resonant \( t\overline{t} \) production in proton-proton collisions at \( \sqrt{s}=8 \) TeV, Phys. Rev. D 93 (2016) 012001 [arXiv:1506.03062] [INSPIRE].
  40. [40]
    Y. Bai and R.J. Hill, Weakly Interacting Stable Pions, Phys. Rev. D 82 (2010) 111701 [arXiv:1005.0008] [INSPIRE].ADSGoogle Scholar
  41. [41]
    ATLAS collaboration, Search for doubly charged Higgs boson production in multi-lepton final states with the ATLAS detector using proton-proton collisions at \( \sqrt{s}=13 \) TeV, Eur. Phys. J. C 78 (2018) 199 [arXiv:1710.09748] [INSPIRE].
  42. [42]
    ATLAS collaboration, Performance assumptions based on full simulation for an upgraded ATLAS detector at a High-Luminosity LHC, ATL-PHYS-PUB-2013-009 (2013).
  43. [43]
    J. Jaeckel and M. Spannowsky, Probing MeV to 90 GeV axion-like particles with LEP and LHC, Phys. Lett. B 753 (2016) 482 [arXiv:1509.00476] [INSPIRE].ADSCrossRefGoogle Scholar
  44. [44]
    A. Freitas and P. Schwaller, Multi-Photon Signals from Composite Models at LHC, JHEP 01 (2011) 022 [arXiv:1010.2528] [INSPIRE].ADSCrossRefGoogle Scholar

Copyright information

© The Author(s) 2018

Authors and Affiliations

  • Daniele Barducci
    • 1
    Email author
  • Stefania De Curtis
    • 2
  • Michele Redi
    • 2
  • Andrea Tesi
    • 2
  1. 1.SISSA and INFN sezione di TriesteTriesteItaly
  2. 2.INFN sezione di FirenzeSesto F.noItaly

Personalised recommendations