Study of Light Scalar Meson Structure in D1D_1 decay

We study the quark structure of the sigma meson through the decay of $D_1(2430)$ meson by constructing an effective Lagrangian for charmed mesons interacting with light mesons based on the chiral symmetry and heavy quark symmetry. Within the linear realization of the chiral symmetry, we include the P-wave charmed mesons ($D_1(2430)$, $D_0(2400)$) as the chiral partners of ($D^\ast$, $D$), and the light scalar mesons as the chiral partner of the pseudoscalar mesons. In the light meson sector, both the $q\bar{q}$ and $qq\bar{q}\bar{q}$ states are incorporated respecting their different U(1)$_A$ transformation properties. We predict the $D_1 \to D\pi\pi$ decay width with two pions in the $I=0,\,l=0$ channel, which can be tested in the future experiment. We find that the width increases with the percentage of the $q\bar{q}$ content in the sigma meson.Comment: 5 pages, 2 figures, Contribution to KMI Inauguration Conference "Quest for the Origin of Particles and the Universe" (KMIIN), 24-26 Nov. 2011, KMI, Nagoya Universit

Anisotropy of Resonant Inelastic X-Ray Scattering at the K Edge of Si:Theoretical Analysis

We investigate theoretically the resonant inelastic x-ray scattering (RIXS) at the $K$ edge of Si on the basis of an ab initio calculation. We calculate the RIXS spectra with systematically varying transfered-momenta, incident-photon energy and incident-photon polarization. We confirm the anisotropy of the experimental spectra by Y. Ma {\it et al}. (Phys. Rev. Lett. 74, 478 (1995)), providing a quantitative explanation of the spectra.Comment: 18 pages, 11 figure

Nearly Mass-Degenerate Majorana Neutrinos: Double Beta Decay and Neutrino Oscillations

Assuming equal tree-level Majorana masses for the standard-model neutrinos, either from the canonical seesaw mechanism or from a heavy scalar triplet, I discuss how their radiative splitting may be relevant to neutrinoless double beta decay and neutrino oscillations.Comment: 12 pages, including 4 figures, talk at NANP9

Notch effects in tensile behavior of AM60 magnesium alloys

The deformation and failure behavior of an AM60 magnesium alloy was investigated using tensile test on circumferentially notched specimens with different notch radii. The strain and stress triaxiality corresponding to the failure point were evaluated using both analytical and finite element analyses. Combining with systematical observations of the fracture surfaces, it is concluded that deformation and failure of AM60 magnesium alloy are notch (constraint) sensitive. The failure mechanisms change from ductile tearing to quasi cleavage with the increase of constraint

Isovector Giant Dipole Resonance of Stable Nuclei in a Consistent Relativistic Random Phase Approximation

A fully consistent relativistic random phase approximation is applied to study the systematic behavior of the isovector giant dipole resonance of nuclei along the $\beta$-stability line in order to test the effective Lagrangians recently developed. The centroid energies of response functions of the isovector giant dipole resonance for stable nuclei are compared with the corresponding experimental data and the good agreement is obtained. It is found that the effective Lagrangian with an appropriate nuclear symmetry energy, which can well describe the ground state properties of nuclei, could also reproduce the isovector giant dipole resonance of nuclei along the $\beta$-stability line.Comment: 4 pages, 1 Postscript figure, to be submitted to Chin.Phys.Let

Semi-classical States in Homogeneous Loop Quantum Cosmology

Semi-classical states in homogeneous loop quantum cosmology (LQC) are constructed by two different ways. In the first approach, we firstly construct an exponentiated annihilation operator. Then a kind of semi-classical (coherent) state is obtained by solving the eigen-equation of that operator. Moreover, we use these coherent states to analyze the semi-classical limit of the quantum dynamics. It turns out that the Hamiltonian constraint operator employed currently in homogeneous LQC has correct classical limit with respect to the coherent states. In the second approach, the other kind of semi-classical state is derived from the mathematical construction of coherent states for compact Lie groups due to Hall.Comment: 13 pages, submitted to CQ

Actions for Vacuum Einstein's Equation with a Killing Symmetry

In a space-time $M$ with a Killing vector field $\xi^a$ which is either everywhere timelike or everywhere spacelike, the collection of all trajectories of $\xi^a$ gives a 3-dimension space $S$. Besides the symmetry-reduced action from that of Einstein-Hilbert, an alternative action of the fields on $S$ is also proposed, which gives the same fields equations as those reduced from the vacuum Einstein equation on $M$.Comment: 8 pages, the difference between the action we proposed and the symmetry-reduced action is clarifie