Unitarity constraints on chiral perturbative amplitudes

Low lying scalar resonances emerge as a necessary part to adjust chiral perturbation theory to experimental data once unitarity constraint is taken into consideration. I review recent progress made in this direction in a model independent approach. Also I briefly review studies on the odd physical properties of these low lying scalar resonances, including in the $\gamma\gamma\to\pi^+\pi^-, \pi^0\pi^0$ processes.Comment: Talk given at: International Workshop on Effective Field Theories: from the pion to the upsilon, February 2-6 2009, Valencia, Spai

Higgs-portal Scalar Dark Matter: Scattering Cross Section and Observable Limits

The simplest Higgs-portal dark matter model is studied in the light of dark matter self-interacting effects on the formation of large scale structures. We show the direct detection limits on the resonant and large mass regions. Finally, we also compare these limits with those at the LHC and Xenon 1T experiments.Comment: Published version, references adde

Scalar resonance at 750 GeV as composite of heavy vector-like fermions

We study a model of scalars which includes both the SM Higgs and a scalar singlet as composites of heavy vector-like fermions. The vector-like fermions are bounded by the super-strong four-fermion interactions. The scalar singlet decays to SM vector bosons through loop of heavy vector-like fermions. We show that the surprisingly large production cross section of di-photon events at 750 GeV resonance and the odd decay properties can all be explained. This model serves as a good model for both SM Higgs and a scalar resonance at 750 GeV.Comment: 12 pages, no figure, references updated, version for publicatio