Higgs decays to γl + l in the standard model

  • Yi Sun
  • Hao-Ran Chang
  • Dao-Neng Gao


The radiative Higgs decays h → γl + l with l = e, μ and τ are analyzed in the standard model using m h = 125GeV. Both tree and one-loop diagrams for the processes are evaluated. In addition to their decay rates and dilepton invariant mass distributions, we focus on the forward-back asymmetries in these modes. Our calculation shows that the forward-backward asymmetries in h → γe + e and h → γμ + μ could be up to 10−2 while in the τ + τ final state, these asymmetries are below 1%. Thus the forwardbackward asymmetries in h → γl + l might be interesting observables in the future precise experiments both to test our understanding of Higgs physics in the standard model and to probe the novel Higgs dynamics in new physics scenarios.


Higgs Physics Rare Decays Standard Model 


  1. [1]
    P.W. Higgs, Broken symmetries, massless particles and gauge fields, Phys. Lett.12 (1964) 132.ADSGoogle Scholar
  2. [2]
    P.W. Higgs, Broken symmetries and the masses of gauge bosons, Phys. Rev. Lett. 13 (1964) 508 [INSPIRE].MathSciNetADSCrossRefGoogle Scholar
  3. [3]
    P.W. Higgs, Spontaneous symmetry breakdown without massless bosons, Phys. Rev. 145 (1966) 1156 [INSPIRE].MathSciNetADSCrossRefGoogle Scholar
  4. [4]
    F. Englert and R. Brout, Broken symmetry and the mass of gauge vector mesons, Phys. Rev. Lett. 13 (1964) 321 [INSPIRE].MathSciNetADSCrossRefGoogle Scholar
  5. [5]
    G. Guralnik, C. Hagen and T. Kibble, Global conservation laws and massless particles, Phys. Rev. Lett. 13 (1964) 585 [INSPIRE].ADSCrossRefGoogle Scholar
  6. [6]
    T. Kibble, Symmetry breaking in nonabelian gauge theories, Phys. Rev. 155 (1967) 1554 [INSPIRE].ADSCrossRefGoogle Scholar
  7. [7]
    ATLAS collaboration, Observation of a new particle in the search for the standard model Higgs boson with the ATLAS detector at the LHC, Phys. Lett. B 716 (2012) 1 [arXiv:1207.7214] [INSPIRE].ADSGoogle Scholar
  8. [8]
    CMS collaboration, Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC, Phys. Lett. B 716 (2012) 30 [arXiv:1207.7235] [INSPIRE].ADSGoogle Scholar
  9. [9]
    CMS collaboration, Observation of a new boson with mass near 125 GeV in pp collisions at \( \sqrt{s}=7 \) and 8TeV, arXiv:1303.4571 [INSPIRE].
  10. [10]
    F.J. Petriello, Kaluza-Klein effects on Higgs physics in universal extra dimensions, JHEP 05 (2002) 003 [hep-ph/0204067] [INSPIRE].ADSCrossRefGoogle Scholar
  11. [11]
    T. Han, H.E. Logan, B. McElrath and L.-T. Wang, Loop induced decays of the little Higgs: Hgg,γγ, Phys. Lett. B 563(2003) 191[Erratum ibid. B 603(2004) 257–259] [hep-ph/0302188] [INSPIRE].ADSGoogle Scholar
  12. [12]
    G. Cacciapaglia, A. Deandrea and J. Llodra-Perez, Higgs → γγ beyond the standard model, JHEP 06 (2009) 054 [arXiv:0901.0927] [INSPIRE].ADSCrossRefGoogle Scholar
  13. [13]
    J. Cao, Z. Heng, T. Liu and J.M. Yang, Di-photon Higgs signal at the LHC: a comparative study for different supersymmetric models, Phys. Lett. B 703 (2011) 462 [arXiv:1103.0631] [INSPIRE].ADSGoogle Scholar
  14. [14]
    S. Heinemeyer, O. Stal and G. Weiglein, Interpreting the LHC Higgs search results in the MSSM, Phys. Lett. B 710 (2012) 201 [arXiv:1112.3026] [INSPIRE].ADSGoogle Scholar
  15. [15]
    P. Ferreira, R. Santos, M. Sher and J.P. Silva, Implications of the LHC two-photon signal for two-Higgs-doublet models, Phys. Rev. D 85 (2012) 077703 [arXiv:1112.3277] [INSPIRE].ADSGoogle Scholar
  16. [16]
    K. Cheung and T.-C. Yuan, Could the excess seen at 124–126 GeV be due to the Randall-Sundrum radion?, Phys. Rev. Lett. 108 (2012) 141602 [arXiv:1112.4146] [INSPIRE].ADSCrossRefGoogle Scholar
  17. [17]
    N. Chen and H.-J. He, LHC signatures of two-Higgs-doublets with fourth family, JHEP 04 (2012) 062 [arXiv:1202.3072] [INSPIRE].ADSCrossRefGoogle Scholar
  18. [18]
    S. Dawson and E. Furlan, A Higgs conundrum with vector fermions, Phys. Rev. D 86 (2012) 015021 [arXiv:1205.4733] [INSPIRE].ADSGoogle Scholar
  19. [19]
    M. Carena, I. Low and C.E. Wagner, Implications of a modified Higgs to diphoton decay width, JHEP 08 (2012) 060 [arXiv:1206.1082] [INSPIRE].ADSCrossRefGoogle Scholar
  20. [20]
    J. Chang, K. Cheung, P.-Y. Tseng and T.-C. Yuan, Distinguishing various models of the 125 GeV boson in vector boson fusion, JHEP 12 (2012) 058 [arXiv:1206.5853] [INSPIRE].ADSCrossRefGoogle Scholar
  21. [21]
    H. An, T. Liu and L.-T. Wang, 125 GeV Higgs boson, enhanced di-photon rate and gauged U(1)P Q -extended MSSM, Phys. Rev. D 86 (2012) 075030 [arXiv:1207.2473] [INSPIRE].ADSGoogle Scholar
  22. [22]
    T. Abe, N. Chen and H.-J. He, LHC Higgs signatures from extended electroweak gauge symmetry, JHEP 01 (2013) 082 [arXiv:1207.4103] [INSPIRE].ADSCrossRefGoogle Scholar
  23. [23]
    A. Joglekar, P. Schwaller and C.E. Wagner, Dark matter and enhanced Higgs to di-photon rate from vector-like leptons, JHEP 12 (2012) 064 [arXiv:1207.4235] [INSPIRE].ADSCrossRefGoogle Scholar
  24. [24]
    L.G. Almeida, E. Bertuzzo, P.A. Machado and R.Z. Funchal, Does H → γγ taste like vanilla new physics?, JHEP 11 (2012) 085 [arXiv:1207.5254] [INSPIRE].ADSCrossRefGoogle Scholar
  25. [25]
    A. Delgado, G. Nardini and M. Quirós, Large diphoton Higgs rates from supersymmetric triplets, Phys. Rev. D 86 (2012) 115010 [arXiv:1207.6596] [INSPIRE].ADSGoogle Scholar
  26. [26]
    M. Hashimoto and V. Miransky, Enhanced diphoton Higgs decay rate and isospin symmetric Higgs boson, Phys. Rev. D 86 (2012) 095018 [arXiv:1208.1305] [INSPIRE].ADSGoogle Scholar
  27. [27]
    T. Kitahara, Vacuum stability constraints on the enhancement of the H → γγ rate in the MSSM, JHEP 11 (2012) 021 [arXiv:1208.4792] [INSPIRE].ADSCrossRefGoogle Scholar
  28. [28]
    S. Chang, S.K. Kang, J.-P. Lee, K.Y. Lee, S.C. Park et al., Comprehensive study of two Higgs doublet model in light of the new boson with mass around 125 GeV, arXiv:1210.3439 [INSPIRE].
  29. [29]
    G. Moreau, Constraining extra-fermion(s) from the Higgs boson data, Phys. Rev. D 87 (2013) 015027 [arXiv:1210.3977] [INSPIRE].ADSGoogle Scholar
  30. [30]
    M. Chala, h → γγ excess and dark matter from composite Higgs models, JHEP 01 (2013) 122 [arXiv:1210.6208] [INSPIRE].ADSCrossRefGoogle Scholar
  31. [31]
    S. Dawson, E. Furlan and I. Lewis, Unravelling an extended quark sector through multiple Higgs production?, Phys. Rev. D 87 (2013) 014007 [arXiv:1210.6663] [INSPIRE].ADSGoogle Scholar
  32. [32]
    K. Choi, S.H. Im, K.S. Jeong and M. Yamaguchi, Higgs mixing and diphoton rate enhancement in NMSSM models, JHEP 02 (2013) 090 [arXiv:1211.0875] [INSPIRE].ADSCrossRefGoogle Scholar
  33. [33]
    C. Han, N. Liu, L. Wu, J.M. Yang and Y. Zhang, Two-Higgs-doublet model with a color-triplet scalar: a joint explanation for top quark forward-backward asymmetry and Higgs decay to diphoton, arXiv:1212.6728 [INSPIRE].
  34. [34]
    W.-Z. Feng and P. Nath, Higgs diphoton rate and mass enhancement with vector-like leptons and the scale of supersymmetry, arXiv:1303.0289 [INSPIRE].
  35. [35]
    T. Kitahara and T. Yoshinaga, Stau with large mass difference and enhancement of the Higgs to diphoton decay rate in the MSSM, arXiv:1303.0461 [INSPIRE].
  36. [36]
    A. Abbasabadi, D. Bowser-Chao, D.A. Dicus and W.W. Repko, Radiative Higgs boson decays Hfermion anti-fermion γ, Phys. Rev. D 55 (1997) 5647 [hep-ph/9611209][INSPIRE].ADSGoogle Scholar
  37. [37]
    A. Abbasabadi and W.W. Repko, Higgs boson decay to muon anti-muon gamma, Phys. Rev. D 62 (2000) 054025 [hep-ph/0004167] [INSPIRE].ADSGoogle Scholar
  38. [38]
    A. Firan and R. Stroynowski, Internal conversions in Higgs decays to two photons, Phys. Rev. D 76 (2007) 057301 [arXiv:0704.3987] [INSPIRE].ADSGoogle Scholar
  39. [39]
    L.-B. Chen, C.-F. Qiao and R.-L. Zhu, Reconstructing the 125 GeV SM Higgs boson through \( \ell \overline{\ell}\gamma \), arXiv:1211.6058 [INSPIRE].
  40. [40]
    D.A. Dicus and W.W. Repko, Calculation of the decay H\( e\overline{e}\gamma \), Phys. Rev. D 87 (2013) 077301 [arXiv:1302.2159] [INSPIRE].ADSGoogle Scholar
  41. [41]
    A.Y. Korchin and V.A. Kovalchuk, Polarization effects in the Higgs boson decay to γZ and test of CP and CPT symmetries, arXiv:1303.0365 [INSPIRE].
  42. [42]
    C.-S. Li, C.-F. Qiao and S.-H. Zhu, Radiative Higgs boson decays H\( f\overline{f}\gamma \) beyond the standard model, Phys. Rev. D 57 (1998) 6928 [hep-ph/9801334] [INSPIRE].ADSGoogle Scholar
  43. [43]
    A.I. Vainshtein, M.B. Voloshin, V.L Zakharov and M.S. Shifman, Low-energy theorems for Higgs meson interaction with photons, Sov. J. Nucl. Phya.30 (1979) 711.Google Scholar
  44. [44]
    L.B. Okua, Leptons and quarks, North-Holland, Amsterdam Netherlands (1982).Google Scholar
  45. [45]
    L. Bergstrom and G. Hulth, Induced Higgs couplings to neutral bosons in e + e collisions, Nucl. Phys. B 259 (1985) 137 [Erratum ibid. B 276 (1986) 744] [INSPIRE].ADSCrossRefGoogle Scholar

Copyright information

© SISSA, Trieste, Italy 2013

Authors and Affiliations

  1. 1.Interdisciplinary Center for Theoretical StudyUniversity of Science and Technology of ChinaHefeiChina
  2. 2.Department of Physics and Institute of Solid State PhysicsSichuan Normal UniversityChengduChina

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