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

We consider the Higgs-dilaton(radion) system using the trace of energy-momentum tensor ($T_{~\mu}^\mu$) with the full Standard Model (SM) gauge symmetry $G_{\rm SM} \equiv SU(3)_c \times SU(2)_L \times U(1)_Y$, and find out that the resulting phenomenology for the Higgs-dilaton(radion) system is distinctly different from the earlier studies based on the $T_{~\mu}^\mu$ with the unbroken subgroup $H_{\rm SM} \equiv SU(3)_c \times U(1)_{\rm em}$ of $G_{\rm SM}$. 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.Comment: Minor corrections, including a few new figures, version appearing in Physics Letters

AdS/QCD approach to the scale-invariant extension of the standard model with a strongly interacting hidden sector

In this paper, we revisit a scale-invariant extension of the standard model (SM) with a strongly interacting hidden sector within AdS/QCD approach. Using the AdS/QCD, we reduce the number of input parameters to three, {\it i.e.} hidden pion decay constant, hidden pion mass and $\tan\beta$ that is defined as the ratio of the vacuum expectation values (VEV) of the singlet scalar field and the SM Higgs boson. As a result, our model has sharp predictability. We perform the phenomenological analysis of the hidden pions which is one of the dark matter (DM) candidates in this model. With various theoretical and experimental constraints we search for the allowed parameter space and find that both resonance and non-resonance solutions are possible. Some typical correlations among various observables such as thermal relic density of hidden pions, Higgs boson signal strengths and DM-nucleon cross section are investigated. We provide some benchmark points for experimental tests.Comment: minor corrections, version appeared in JHE