Neutrino Masses from Cosmological Probes in Interacting Neutrino Dark-Energy Models

We investigate whether interaction between massive neutrinos and quintessence scalar field is the origin of the late time accelerated expansion of the universe. We present explicit formulas of the cosmological linear perturbation theory in the neutrinos probes of dark-energy model, and calculate cosmic microwave background anisotropies and matter power spectra. In these models, the evolution of the mass of neutrinos is determined by the quintessence scalar field, which is responsible for a varying effective equation of states: $\omega_{eff}(z)$ goes down -1. We consider several types of scalar field potential and put constraints on the coupling parameter between neutrinos and dark energy. By combining data from cosmic microwave background (CMB) experiments including the WMAP 3-year results, large scale structure with 2dFGRS data sets, we constrain the hypothesis of massive neutrinos in the mass-varying neutrino scenario. Assuming the flatness of the universe, the constraint we can derive from the current observation is $\sum m_{\nu} < 0.45$ eV at 1$\sigma$ (0.87 eV at 2$\sigma$) confidence level for the sum over three species of neutrinos. The dynamics of scalar field and the impact of scalar field perturbations on cosmic microwave background anisotropies are discussed. We also discuss on the instability issue of the our model and confirm that neutrinos are stable against the density fluctuation.Comment: Latex, 34 pages, 11 figures, final version to appear in JHE

Determination of weak phases ϕ2\phi_2 and ϕ3\phi_3 from B→ππ,KπB\to \pi\pi,K\pi in the pQCD method

We look at two methods to determine the weak phases $\phi_2$ and $\phi_3$ from $B \to \pi\pi$ and $K\pi$ decays within the perturbative QCD approach. We obtain quite interesting bounds on $\phi_2$ and $\phi_3$ from recent experimental measurements in asymmetric B-factory: $55^o \leq \phi_2 \leq 100^o$ and $51^o \leq \phi_3 \leq 129^o$. Specially we predict the possibility of large direct CP violation effect in $B^0 \to \pi^{+}\pi^{-}$ decay with $A_{cp}^{dir}(B\to \pi^{+} \pi^{-})=(23\pm7)$ %.Comment: 6 pages, Latex, 3 figures, typos corrected. Presented at Workshop on CKM Unitarity Triangle (CERN 2002-2003), Geneva, Switzerland, 13-16 Feb 200

Probing for Dynamics of Dark-Energy in Mass Varying Neutrinos: Cosmic Microwave Background Radiation and Large Scale Structure

We present cosmological perturbation theory in neutrino probe interacting dark-energy models, and calculate cosmic microwave background anisotropies and matter power spectrum. In these models, the evolution of the mass of neutrinos is determined by the quintessence scalar field, which is responsible for the cosmic acceleration today. We consider several types of scalar field potentials and put constraints on the coupling parameter between neutrinos and dark energy. Assuming the flatness of the universe, the constraint we can derive from the current observation is $\sum m_{\nu} < 0.87 eV$ at the 95 % confidence level for the sum over three species of neutrinos.Comment: 12 pages, 8 figures, Present in conferences COSPA-2006, NEPSE-2007 and Yong-Pyung APCTP-200

Fat penguins and imaginary penguins in perturbative QCD

We evaluate $B\to K\pi$ decay amplitudes in perturbative QCD picture. It is found that penguin contributions are dynamically enhanced by nearly 50% compared to those assumed in the factorization approximation. It is also shown that annihilation diagrams are not negligible, and give large strong phases. Our results for branching ratios of $B\to K\pi$ decays for a representative parameter set are consistent with data. We evaluate $B\to K\pi$ decay amplitudes in perturbative QCD picture. It is found that penguin contributions are dynamically enhanced by nearly 50% compared to those assumed in the factorization approximation. It is also shown that annihilation diagrams are not negligible, and give large strong phases. Our results for branching ratios of $B\to K\pi$ decays for a representative parameter set are consistent with data.Comment: 11 pages, Latex2e, 3 figures, corrected some typos and reduced no. of figures. Changed the abstract, Submit at PL