Higgs–dilaton(radion) system confronting the LHC Higgs data

We consider the Higgs–dilaton(radion) system using the trace of energy–momentum tensor (Tμμ) with the full Standard Model (SM) gauge symmetry GSM≡SU(3)c×SU(2)L×U(1)Y, and find out that the resulting phenomenology for the Higgs–dilaton(radion) system is distinctly different from the earlier studies based on the Tμμ with the unbroken subgroup HSM≡SU(3)c×U(1)em of GSM. After electroweak symmetry breaking (EWSB), the SM Higgs boson and dilaton(radion) will mix with each other, and there appear two Higgs-like scalar bosons and the Higgs–dilaton mixing changes the scalar phenomenology in interesting ways. The signal strengths for the gg-initiated channels could be modified significantly compared with the SM predictions due to the QCD scale anomaly and the Higgs–dilaton(radion) mixing, whereas anomaly contributions are almost negligible for other channels. We also discuss the self-couplings and the signal strengths of the 126 GeV scalar boson in various channels and possible constraints from the extra light/heavy scalar boson. The Higgs–dilaton(radion) system considered in this work has a number of distinctive features that could be tested by the upcoming LHC running and at the ILC.