We report an observation of the $B^{pm} to J/psi eta K^{pm}$ and $B^0 to J/psi eta K^0_S$ decays using 772$times 10^{6}$ $Bbar{B}$ pairs collected at the $Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider.
We obtain the branching fractions ${cal B}(B^{pm}rightarrow J/psieta K^{pm})=(1.27pm 0.11{rm (stat.)pm 0.11{rm (syst.)})}times10^{-4}$ and ${cal B}(B^0to J/psi eta K^0_S)=(5.22 pm 0.78 {rm(stat.)} pm 0.49{rm(syst.)})times10^{-5}$. We search for a new narrow charmonium(-like) state $X$ in the $J/psi eta$ mass spectrum and find no significant excess. We set upper limits on the product of branching fractions, ${cal B}(B^pm to XK^pm){cal B}(X to J/psi eta)$, at 3872 MeV$/c^2$ where a $C$-odd partner of X(3872) may exist, at $psi(4040)$ and $psi(4160)$ assuming their known mass and width, and over a range from 3.8 to 4.8 GeV$/c^2$. % at a 5 MeV$/c^2$ step. The obtained upper limits at 90% confidence level for $X^{C{rm -odd}}(3872)$, $psi(4040)$ and $psi(4160)$ are 3.8$times 10^{-6}$, 15.5$times 10^{-6}$ and 7.4$times 10^{-6}$, respectively.
The elementary excitations of vibration in solids are phonons. But in liquids phonons are extremely short-lived and marginalized. In this letter through classical and ab-initio molecular dynamics simulations of the liquid state of various metallic sy
stems we show that different excitations, the local configurational excitations in the atomic connectivity network, are the elementary excitations in high temperature metallic liquids. We also demonstrate that the competition between the configurational excitations and phonons determines the so-called crossover phenomenon in liquids. These discoveries open the way to the explanation of various complex phenomena in liquids, such as fragility and the rapid increase in viscosity toward the glass transition, in terms of these excitations.
We report an extension of the smoothed profile method (SPM)[Y. Nakayama, K. Kim, and R. Yamamoto, Eur. Phys. J. E {bf 26}, 361(2008)], a direct numerical simulation method for calculating the complex modulus of the dispersion of particles, in which w
e introduce a temporally oscillatory external force into the system. The validity of the method was examined by evaluating the storage $G(omega)$ and loss $G(omega)$ moduli of a system composed of identical spherical particles dispersed in an incompressible Newtonian host fluid at volume fractions of $Phi=0$, 0.41, and 0.51. The moduli were evaluated at several frequencies of shear flow; the shear flow used here has a zigzag profile, as is consistent with the usual periodic boundary conditions.
