Toward a coherent solution of diphoton and flavor anomalies

  • Dario Buttazzo
  • Admir Greljo
  • Gino Isidori
  • David Marzocca
Open Access
Regular Article - Theoretical Physics


We propose a coherent explanation for the 750 GeV diphoton anomaly and the hints of deviations from Lepton Flavor Universality in B decays in terms a new strongly interacting sector with vectorlike confinement. The diphoton excess arises from the decay ofone of the pseudo-Nambu-Goldstone bosons of the new sector, while the flavor anomalies are a manifestation of the exchange of the corresponding vector resonances (with masses in the 1.5-2.5 TeV range). We provide explicit examples (with detailed particle content and group structure) of the new sector, discussing both the low-energy flavor-physics phenomenology and the signatures at high p T . We show that specific models can provide an excellent fit to all available data. A key feature of all realizations is a sizable broad excess in the tails of τ + τ invariant mass distribution in p pτ + τ , that should be accessible at the LHC in the near future.


Beyond Standard Model Heavy Quark 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]
    ATLAS collaboration, Search for resonances in diphoton events with the ATLAS detector at \( \sqrt{s}=13 \) TeV, ATLAS-CONF-2016-018 (2016).
  2. [2]
    CMS collaboration, Search for new physics in high mass diphoton events in 3.3 fb−1 of proton-proton collisions at \( \sqrt{s}=13 \) TeV and combined interpretation of searches at 8 TeV and 13 TeV, CMS-PAS-EXO-16-018 (2016).
  3. [3]
    CMS collaboration, Search for new physics in high mass diphoton events in proton-proton collisions at \( \sqrt{s}=13 \) TeV, CMS-PAS-EXO-15-004 (2015).
  4. [4]
    ATLAS collaboration, Search for resonances decaying to photon pairs in 3.2 fb −1 of pp collisions at \( \sqrt{s}=13 \) TeV with the ATLAS detector, ATLAS-CONF-2015-081 (2015).
  5. [5]
    CMS collaboration, Search for new resonances in the diphoton final state in the range between 150 and 850 GeV in pp collisions at \( \sqrt{s}=8 \) TeV, CMS-PAS-HIG-14-006 (2015).
  6. [6]
    ATLAS collaboration, Search for high-mass diphoton resonances in pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, Phys. Rev. D 92 (2015) 032004 [arXiv:1504.05511] [INSPIRE].
  7. [7]
    BaBar collaboration, J.P. Lees et al., Measurement of an Excess of \( \overline{B}\to {D}^{\left(\ast \right)}\tau -\overline{\nu}\tau \) Decays and Implications for Charged Higgs Bosons, Phys. Rev. D 88 (2013) 072012 [arXiv:1303.0571] [INSPIRE].
  8. [8]
    Belle collaboration, M. Huschle et al., Measurement of the branching ratio of \( \overline{B}\to {D}^{\left(\ast \right)}\tau -\overline{\nu}\tau \) relative to \( \overline{B}\to {D}^{\left(\ast \right)}\ell -\overline{\nu}\ell \) decays with hadronic tagging at Belle, Phys. Rev. D 92 (2015) 072014 [arXiv:1507.03233] [INSPIRE].
  9. [9]
    LHCb collaboration, Measurement of the ratio of branching fractions \( \mathrm{\mathcal{B}}\left({\overline{B}}^0\to {D}^{\ast +}{\tau}^{-}{\overline{\nu}}_{\tau}\right)/\mathrm{\mathcal{B}}\left({\overline{B}}^0\to {D}^{\ast +}{\mu}^{-}{\overline{\nu}}_{\mu}\right) \), Phys. Rev. Lett. 115 (2015) 111803 [arXiv:1506.08614] [INSPIRE].
  10. [10]
    LHCb collaboration, Test of lepton universality using B +K + + decays, Phys. Rev. Lett. 113 (2014) 151601 [arXiv:1406.6482] [INSPIRE].
  11. [11]
    LHCb collaboration, Angular analysis of the B 0K ∗0 μ + μ decay, LHCb-CONF-2015-002 (2015).
  12. [12]
    C. Kilic, T. Okui and R. Sundrum, Vectorlike Confinement at the LHC, JHEP 02 (2010) 018 [arXiv:0906.0577] [INSPIRE].ADSCrossRefzbMATHGoogle Scholar
  13. [13]
    C. Kilic and T. Okui, The LHC Phenomenology of Vectorlike Confinement, JHEP 04 (2010) 128 [arXiv:1001.4526] [INSPIRE].ADSCrossRefzbMATHGoogle Scholar
  14. [14]
    R. Franceschini et al., What is the γγ resonance at 750 GeV?, JHEP 03 (2016) 144 [arXiv:1512.04933] [INSPIRE].ADSCrossRefGoogle Scholar
  15. [15]
    K. Harigaya and Y. Nomura, Composite Models for the 750 GeV Diphoton Excess, Phys. Lett. B 754 (2016) 151 [arXiv:1512.04850] [INSPIRE].ADSCrossRefGoogle Scholar
  16. [16]
    Y. Nakai, R. Sato and K. Tobioka, Footprints of New Strong Dynamics via Anomaly and the 750 GeV Diphoton, Phys. Rev. Lett. 116 (2016) 151802 [arXiv:1512.04924] [INSPIRE].ADSCrossRefGoogle Scholar
  17. [17]
    L. Bian, N. Chen, D. Liu and J. Shu, Hidden confining world on the 750 GeV diphoton excess, Phys. Rev. D 93 (2016) 095011 [arXiv:1512.05759] [INSPIRE].ADSGoogle Scholar
  18. [18]
    N. Craig, P. Draper, C. Kilic and S. Thomas, Shedding Light on Diphoton Resonances, Phys. Rev. D 93 (2016) 115023 [arXiv:1512.07733] [INSPIRE].ADSGoogle Scholar
  19. [19]
    Y. Bai, J. Berger and R. Lu, 750 GeV dark pion: Cousin of a dark G-parity odd WIMP, Phys. Rev. D 93 (2016) 076009 [arXiv:1512.05779] [INSPIRE].ADSGoogle Scholar
  20. [20]
    K. Harigaya and Y. Nomura, A Composite Model for the 750 GeV Diphoton Excess, JHEP 03 (2016) 091 [arXiv:1602.01092] [INSPIRE].ADSCrossRefGoogle Scholar
  21. [21]
    M. Redi, A. Strumia, A. Tesi and E. Vigiani, Di-photon resonance and Dark Matter as heavy pions, JHEP 05 (2016) 078 [arXiv:1602.07297] [INSPIRE].ADSCrossRefGoogle Scholar
  22. [22]
    K. Harigaya and Y. Nomura, Hidden Pion Varieties in Composite Models for Diphoton Resonances, arXiv:1603.05774 [INSPIRE].
  23. [23]
    J.F. Kamenik and M. Redi, Back to 1974: The \( \mathcal{Q} \) -onium, Phys. Lett. B 760 (2016) 158 [arXiv:1603.07719] [INSPIRE].ADSCrossRefGoogle Scholar
  24. [24]
    D. Buttazzo, A. Greljo and D. Marzocca, Knocking on new physics’ door with a scalar resonance, Eur. Phys. J. C 76 (2016) 116 [arXiv:1512.04929] [INSPIRE].ADSCrossRefGoogle Scholar
  25. [25]
    M. Low, A. Tesi and L.-T. Wang, A pseudoscalar decaying to photon pairs in the early LHC Run 2 data, JHEP 03 (2016) 108 [arXiv:1512.05328] [INSPIRE].ADSCrossRefGoogle Scholar
  26. [26]
    B. Bellazzini, R. Franceschini, F. Sala and J. Serra, Goldstones in Diphotons, JHEP 04 (2016) 072 [arXiv:1512.05330] [INSPIRE].ADSCrossRefGoogle Scholar
  27. [27]
    J.M. No, V. Sanz and J. Setford, See-saw composite Higgs model at the LHC: Linking naturalness to the 750 GeV diphoton resonance, Phys. Rev. D 93 (2016) 095010 [arXiv:1512.05700] [INSPIRE].ADSGoogle Scholar
  28. [28]
    A. Belyaev, G. Cacciapaglia, H. Cai, T. Flacke, A. Parolini and H. Serôdio, Singlets in composite Higgs models in light of the LHC 750 GeV diphoton excess, Phys. Rev. D 94 (2016) 015004 [arXiv:1512.07242] [INSPIRE].ADSGoogle Scholar
  29. [29]
    E. Molinaro, F. Sannino and N. Vignaroli, Minimal Composite Dynamics versus Axion Origin of the Diphoton excess, arXiv:1512.05334 [INSPIRE].
  30. [30]
    S. Matsuzaki and K. Yamawaki, 750 GeV Diphoton Signal from One-Family Walking Technipion, Mod. Phys. Lett. A 31 (2016) 1630016 [arXiv:1512.05564] [INSPIRE].ADSCrossRefGoogle Scholar
  31. [31]
    E. Molinaro, F. Sannino and N. Vignaroli, Collider Tests of (Composite) Diphoton Resonances, arXiv:1602.07574 [INSPIRE].
  32. [32]
    A. Greljo, G. Isidori and D. Marzocca, On the breaking of Lepton Flavor Universality in B decays, JHEP 07 (2015) 142 [arXiv:1506.01705] [INSPIRE].ADSCrossRefGoogle Scholar
  33. [33]
    R. Barbieri, G. Isidori, A. Pattori and F. Senia, Anomalies in B-decays and U(2) flavour symmetry, Eur. Phys. J. C 76 (2016) 67 [arXiv:1512.01560] [INSPIRE].ADSCrossRefGoogle Scholar
  34. [34]
    R. Barbieri, G. Isidori, J. Jones-Perez, P. Lodone and D.M. Straub, U(2) and Minimal Flavour Violation in Supersymmetry, Eur. Phys. J. C 71 (2011) 1725 [arXiv:1105.2296] [INSPIRE].ADSCrossRefGoogle Scholar
  35. [35]
    F. Goertz, J.F. Kamenik, A. Katz and M. Nardecchia, Indirect Constraints on the Scalar Di-Photon Resonance at the LHC, JHEP 05 (2016) 187 [arXiv:1512.08500] [INSPIRE].ADSCrossRefGoogle Scholar
  36. [36]
    G. Bélanger and C. Delaunay, A Dark Sector for g μ − 2, R K and a Diphoton Resonance, arXiv:1603.03333 [INSPIRE].
  37. [37]
    M. Bauer and M. Neubert, Flavor anomalies, the 750 GeV diphoton excess and a dark matter candidate, Phys. Rev. D 93 (2016) 115030 [arXiv:1512.06828] [INSPIRE].ADSGoogle Scholar
  38. [38]
    C.W. Murphy, Vector Leptoquarks and the 750 GeV Diphoton Resonance at the LHC, Phys. Lett. B 757 (2016) 192 [arXiv:1512.06976] [INSPIRE].ADSCrossRefGoogle Scholar
  39. [39]
    F.F. Deppisch, S. Kulkarni, H. Päs and E. Schumacher, Leptoquark patterns unifying neutrino masses, flavor anomalies and the diphoton excess, Phys. Rev. D 94 (2016) 013003 [arXiv:1603.07672] [INSPIRE].ADSGoogle Scholar
  40. [40]
    S.L. Glashow, D. Guadagnoli and K. Lane, Lepton Flavor Violation in B Decays?, Phys. Rev. Lett. 114 (2015) 091801 [arXiv:1411.0565] [INSPIRE].ADSCrossRefGoogle Scholar
  41. [41]
    D.B. Kaplan, Flavor at SSC energies: A New mechanism for dynamically generated fermion masses, Nucl. Phys. B 365 (1991) 259 [INSPIRE].ADSCrossRefGoogle Scholar
  42. [42]
    R. Barbieri, D. Buttazzo, F. Sala and D.M. Straub, Flavour physics from an approximate U(2)3 symmetry, JHEP 07 (2012) 181 [arXiv:1203.4218] [INSPIRE].ADSCrossRefGoogle Scholar
  43. [43]
    C. Pica and F. Sannino, Anomalous Dimensions of Conformal Baryons, arXiv:1604.02572 [INSPIRE].
  44. [44]
    B. Gripaios, M. Nardecchia and S.A. Renner, Composite leptoquarks and anomalies in B-meson decays, JHEP 05 (2015) 006 [arXiv:1412.1791] [INSPIRE].ADSCrossRefGoogle Scholar
  45. [45]
    L. Calibbi, A. Crivellin and T. Ota, Effective Field Theory Approach to bsℓℓ (′) , \( B\to {K}^{\left(\ast \right)}\nu \overline{\nu} \) and B→D (∗) τν with Third Generation Couplings, Phys. Rev. Lett. 115(2015) 181801 [arXiv:1506.02661] [INSPIRE].ADSCrossRefGoogle Scholar
  46. [46]
    M. Bauer and M. Neubert, Minimal Leptoquark Explanation for the \( {R}_{{{}_D}_{\left(\ast \right)}} \) , RK and (g − 2)g Anomalies, Phys. Rev. Lett. 116 (2016) 141802 [arXiv:1511.01900] [INSPIRE].ADSCrossRefGoogle Scholar
  47. [47]
    S. Fajfer and N. Košnik, Vector leptoquark resolution of R K and R D(∗) puzzles, Phys. Lett. B 755 (2016) 270 [arXiv:1511.06024] [INSPIRE].ADSCrossRefGoogle Scholar
  48. [48]
    B. Bhattacharya, A. Datta, D. London and S. Shivashankara, Simultaneous Explanation of the R K and R(D (∗)) Puzzles, Phys. Lett. B 742 (2015) 370 [arXiv:1412.7164] [INSPIRE].ADSCrossRefzbMATHGoogle Scholar
  49. [49]
    R. Alonso, B. Grinstein and J. Martin Camalich, Lepton universality violation and lepton flavor conservation in B-meson decays, JHEP 10 (2015) 184 [arXiv:1505.05164] [INSPIRE].ADSCrossRefGoogle Scholar
  50. [50]
    M. Freytsis, Z. Ligeti and J.T. Ruderman, Flavor models for \( B\to {D}^{\left(\ast \right)}\tau \overline{\nu} \), Phys. Rev. D 92 (2015) 054018 [arXiv:1506.08896] [INSPIRE].ADSCrossRefGoogle Scholar
  51. [51]
    I. Doršner, S. Fajfer, A. Greljo, J.F. Kamenik and N. Košnik, Physics of leptoquarks in precision experiments and at particle colliders, Phys. Rept. 641 (2016) 1 [arXiv:1603.04993] [INSPIRE].ADSMathSciNetCrossRefGoogle Scholar
  52. [52]
    P. Goldenzweig, \( \overline{B}\to {D^{\Big(}}^{\ast \Big)}\tau\ {\overline{\nu}}_{\tau } \) decays with hadronic and semileptonic tagging at Belle, talk presented at Moriond 2016, La Thuile Italy (2016).Google Scholar
  53. [53]
    Fermilab Lattice, MILC collaboration, A. Bazavov et al., B (s)0 -mixing matrix elements from lattice QCD for the Standard Model and beyond, Phys. Rev. D 93 (2016) 113016 [arXiv:1602.03560] [INSPIRE].
  54. [54]
    M. Blanke and A.J. Buras, Universal Unitarity Triangle 2016 and the tension between ΔM s,d and ε K in CMFV models, Eur. Phys. J. C 76 (2016) 197 [arXiv:1602.04020] [INSPIRE].ADSCrossRefGoogle Scholar
  55. [55]
    W. Altmannshofer and D.M. Straub, New physics in bs transitions after LHC run 1, Eur. Phys. J. C 75 (2015) 382 [arXiv:1411.3161] [INSPIRE].ADSCrossRefGoogle Scholar
  56. [56]
    S. Descotes-Genon, L. Hofer, J. Matias and J. Virto, Global analysis of bsℓℓ anomalies, JHEP 06 (2016) 092 [arXiv:1510.04239] [INSPIRE].ADSCrossRefGoogle Scholar
  57. [57]
    Particle Data Group collaboration, K.A. Olive et al., Review of Particle Physics, Chin. Phys. C 38 (2014) 090001 [INSPIRE].
  58. [58]
    L.A. Harland-Lang, A.D. Martin, P. Motylinski and R.S. Thorne, Parton distributions in the LHC era: MMHT 2014 PDFs, Eur. Phys. J. C 75 (2015) 204 [arXiv:1412.3989] [INSPIRE].ADSCrossRefGoogle Scholar
  59. [59]
    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
  60. [60]
    A. Alloul, N.D. Christensen, C. Degrande, C. Duhr and B. Fuks, FeynRules 2.0 — A complete toolbox for tree-level phenomenology, Comput. Phys. Commun. 185 (2014) 2250 [arXiv:1310.1921] [INSPIRE].
  61. [61]
    ATLAS collaboration, A search for high-mass resonances decaying to τ + τ in pp collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, JHEP 07 (2015) 157 [arXiv:1502.07177] [INSPIRE].
  62. [62]
    Y. Bai, V. Barger and J. Berger, Constraints on color-octet companions of a 750 GeV heavy pion from dijet and photon plus jet resonance searches, Phys. Rev. D 94 (2016) 011701 [arXiv:1604.07835] [INSPIRE].ADSGoogle Scholar
  63. [63]
    ATLAS collaboration, Search for new phenomena in the dijet mass distribution using pp collision data at \( \sqrt{s}=8 \) TeV with the ATLAS detector, Phys. Rev. D 91 (2015) 052007 [arXiv:1407.1376] [INSPIRE].
  64. [64]
    CMS collaboration, Search for resonances and quantum black holes using dijet mass spectra in proton-proton collisions at \( \sqrt{s}=8 \) TeV, Phys. Rev. D 91 (2015) 052009 [arXiv:1501.04198] [INSPIRE].
  65. [65]
    ATLAS collaboration, Search for new phenomena in dijet mass and angular distributions from pp collisions at \( \sqrt{s}=13 \) TeV with the ATLAS detector, Phys. Lett. B 754 (2016) 302 [arXiv:1512.01530] [INSPIRE].
  66. [66]
    ATLAS collaboration, A search for tt resonances using lepton-plus-jets events in proton-proton collisions at \( \sqrt{s}=8 \) TeV with the ATLAS detector, JHEP 08 (2015) 148 [arXiv:1505.07018] [INSPIRE].
  67. [67]
    CMS collaboration, Search for tt resonances in semileptonic final state, CMS-PAS-B2G-12-006 (2012).
  68. [68]
    CMS collaboration, Search for Third-Generation Scalar Leptoquarks in the tτ Channel in Proton-Proton Collisions at \( \sqrt{s=8} \) TeV, JHEP 07 (2015) 042 [arXiv:1503.09049] [INSPIRE].
  69. [69]
    CMS collaboration, Search for pair production of third-generation scalar leptoquarks and top squarks in proton-proton collisions at \( \sqrt{s}=8 \) TeV, Phys. Lett. B 739 (2014) 229 [arXiv:1408.0806] [INSPIRE].

Copyright information

© The Author(s) 2016

Authors and Affiliations

  • Dario Buttazzo
    • 1
  • Admir Greljo
    • 1
    • 2
  • Gino Isidori
    • 1
  • David Marzocca
    • 1
  1. 1.Physik-InstitutUniversität ZürichZürichSwitzerland
  2. 2.Faculty of ScienceUniversity of SarajevoSarajevoBosnia and Herzegovina

Personalised recommendations