Last modified 3 years ago Last modified on 06/22/14 04:10:08

Minimal Dilaton Model (MDM)


  • Junjie Cao
    • Henan Normal University; Center for High Energy Physics, Peking University
    • junjiec@…
  • Xiqing Hao
    • Henan Normal University
    • haoxq@…
  • Zhaoxia Heng
    • Henan Normal University
    • zhaoxiaheng@…
  • Liangliang Shang
    • Henan Normal University
    • shlwell1988@…
  • Yang Zhang
    • Institute of Theoretical Physics, Academia Sinica
    • phyzhangyang@…

Description of the model

This model is an extension of the SM by introducing a linearized singlet dilaton field S and a vector-like top partner T with the same quantum number as the right-handed top quark. The low energy effective Lagrangian of the MDM is given by [1] [2] [3]:

the low energy effective Lagrangian of the MDM

where LSM is the part of the SM Lagrangian without the Higgs potential, M presents the scale of a certain strong dynamics in which the fields T and S are involved, q3L is the SU(2)L left-handed quark doublet of the third generation, and MH, MS, λS, κ and λH are all free parameters describing the new Higgs potential.

Model files


  • Except the free parameters in the SM, there are still five free parameters in the MDM:
    • f: the vacuum expectation value of Dilaton;
    • θL: the mixing angle of top and top partner;
    • θS: the mixing angle of Higgs and Dilaton;
    • ms: the mass of dilaton-boson;
    • mt': the mass of top partner.
  • The dilaton-boson mass and width are set using the parameters MsDM and WsDM, respectively.
  • The top partner mass and width are set using the parameters MTP and WTP, respectively.
  • The vacuum expectation value of Dilaton is given by vevf.
  • The tangent value of Higgs-Dilaton mixing angle is set by ts.
  • The sine value of top and top partner mixing angle is set by sl.


The Feynman rules were computed by hand and compared with the FeynRules vertices and found to agree. Furthermore, the three main partial decay widths of top partner were calculated by hand, compared with the numerical results both in CalcHEP with Feynman gauge and Unitary gauge and in MadGraph with Unitary gauge, and found to agree. We have uploaded our model file in the FeynRules validation web and checked our model file. Moreover, the hermiticity of the Lagrangian was tested at the Feynman rules level.


[1] Tomohiro Abe, Ryuichiro Kitano, Yasufumi Konishi, Kin-ya Oda, Joe Sato and Shohei Sugiyama, Minimal Dilaton Model, Phys. Rev. D86 (2012) 115016, arXiv:1209.4544 [hep-ph].

[2] Junjie Cao, Yangle He, Peiwen Wu, Mengchao Zhang and Jingya Zhu, Higgs phenomenology in the Minimal Dilaton Model after Run I of the LHC, JHEP 1401 (2014) 150, arXiv:1311.6661 [hep-ph].

[3] Junjie Cao, Zhaoxia Heng, Dongwei Li, Liangliang Shang, Peiwen Wu, Higgs-strahlung production process e+e → Zh at the future Higgs factory in the Minimal Dilaton Model, arXiv:1405.4489 [hep-ph].