Nucleon magnetic form factors with non-local chiral effective Lagrangian

Chiral perturbation theory is a powerful method to investigate the hadron properties. We apply the non-local chiral effective Lagrangian to study nucleon magnetic form factors. The octet and decuplet intermediate states are included in the one loop calculation. With the modified propagators and non-local interactions, the loop integral is convergent. The obtained proton and neutron magnetic form factors are both reasonable up to relatively large $Q^2$.Comment: 11 pages, 7 figures, 1 tables. arXiv admin note: text overlap with arXiv:1210.507

The phase between the three gluon and one photon amplitudes in quarkonium decays

The phase between three-gluon and one-photon amplitudes in psi(2S) and psi(3770) decays is analyzed.Comment: 5 pages, 4 figures, Talk given at Hadron 03: 10th International Conference on Hadron Spectroscopy, Aschaffenburg, Germany, 31 Aug - 6 Sep 200

Optical spectroscopy study of Nd(O,F)BiS2 single crystals

We present an optical spectroscopy study on F-substituted NdOBiS$_2$ superconducting single crystals grown using KCl/LiCl flux method. The measurement reveals a simple metallic response with a relatively low screened plasma edge near 5000 \cm. The plasma frequency is estimated to be 2.1 eV, which is much smaller than the value expected from the first-principles calculations for an electron doping level of x=0.5, but very close to the value based on a doping level of 7$\%$ of itinerant electrons per Bi site as determined by ARPES experiment. The energy scales of the interband transitions are also well reproduced by the first-principles calculations. The results suggest an absence of correlation effect in the compound, which essentially rules out the exotic pairing mechanism for superconductivity or scenario based on the strong electronic correlation effect. The study also reveals that the system is far from a CDW instability as being widely discussed for a doping level of x=0.5.Comment: 5 pages, 5 figure

Liquid-gas phase transition in nuclear matter including strangeness

We apply the chiral SU(3) quark mean field model to study the properties of strange hadronic matter at finite temperature. The liquid-gas phase transition is studied as a function of the strangeness fraction. The pressure of the system cannot remain constant during the phase transition, since there are two independent conserved charges (baryon and strangeness number). In a range of temperatures around 15 MeV (precise values depending on the model used) the equation of state exhibits multiple bifurcates. The difference in the strangeness fraction $f_s$ between the liquid and gas phases is small when they coexist. The critical temperature of strange matter turns out to be a non-trivial function of the strangeness fraction.Comment: 15 pages, 7 figure

Polarized Curvature Radiation in Pulsar Magnetosphere

The propagation of polarized emission in pulsar magnetosphere is investigated in this paper. The polarized waves are generated through curvature radiation from the relativistic particles streaming along curved magnetic field lines and co-rotating with the pulsar magnetosphere. Within the 1/{\deg} emission cone, the waves can be divided into two natural wave mode components, the ordinary (O) mode and the extraord nary (X) mode, with comparable intensities. Both components propagate separately in magnetosphere, and are aligned within the cone by adiabatic walking. The refraction of O-mode makes the two components separated and incoherent. The detectable emission at a given height and a given rotation phase consists of incoherent X-mode and O-mode components coming from discrete emission regions. For four particle-density models in the form of uniformity, cone, core and patches, we calculate the intensities for each mode numerically within the entire pulsar beam. If the co-rotation of relativistic particles with magnetosphere is not considered, the intensity distributions for the X-mode and O-mode components are quite similar within the pulsar beam, which causes serious depolarization. However, if the co-rotation of relativistic particles is considered, the intensity distributions of the two modes are very different, and the net polarization of out-coming emission should be significant. Our numerical results are compared with observations, and can naturally explain the orthogonal polarization modes of some pulsars. Strong linear polarizations of some parts of pulsar profile can be reproduced by curvature radiation and subsequent propagation effect.Comment: 12 pages, 9 figures, Accepted for publication in MNRA

Optical properties of TlNi2Se2: Observation of pseudogap formation

The quasi-two-dimensional nickel chalcogenides $TlNi_2Se_2$ is a newly discovered superconductor. We have performed optical spectroscopy study on $TlNi_2Se_2$ single crystals over a broad frequency range at various temperatures. The overall optical reflectance spectra are similar to those observed in its isostructure $BaNi_2As_2$. Both the suppression in $R(\omega)$ and the peaklike feature in $\sigma_1(\omega)$ suggest the progressive formation of a pseudogap feature in the midinfrared range with decreasing temperatures, which might be originated from the dynamic local fluctuation of charge-density-wave (CDW) instability. We propose that the CDW instability in $TlNi_2Se_2$ is driven by the saddle points mechanism, due to the existence of van Hove singularity very close to the Fermi energy.Comment: 5 pages, 4 figure

Background stratospheric aerosol reference model

In this analysis, a reference background stratospheric aerosol optical model is developed based on the nearly global SAGE 1 satellite observations in the non-volcanic period from March 1979 to February 1980. Zonally averaged profiles of the 1.0 micron aerosol extinction for the tropics and the mid- and high-altitudes for both hemispheres are obtained and presented in graphical and tabulated form for the different seasons. In addition, analytic expressions for these seasonal global zonal means, as well as the yearly global mean, are determined according to a third order polynomial fit to the vertical profile data set. This proposed background stratospheric aerosol model can be useful in modeling studies of stratospheric aerosols and for simulations of atmospheric radiative transfer and radiance calculations in atmospheric remote sensing

New Primordial-Magnetic-Field Limit from The Latest LIGO S5 data

Since the energy momentum tensor of a magnetic field always contains a spin-2 component in its anisotropic stress, stochastic primordial magnetic field (PMF) in the early universe must generate stochastic gravitational wave (GW) background. This process will greatly affect the relic gravitational wave (RGW), which is one of major scientific goals of the laser interferometer GW detections. Recently, the fifth science (S5) run of laser interferometer gravitational-wave observatory (LIGO) gave a latest upper limit $\Omega_{GW}<6.9\times10^{-6}$ on the RGW background. Utilizing this upper limit, we derive new PMF Limits: for a scale of galactic cluster $\lambda=1$ Mpc, the amplitude of PMF, that produced by the electroweak phase transition (EPT), has to be weaker than $B_{\lambda} \leq 4\times 10^{-7}$ Gauss; for a scale of supercluster $\lambda=100$ Mpc, the amplitude of PMF has to be weaker than $B_{\lambda} \leq 9\times 10^{-11}$ Gauss. In this manner, GW observation has potential to make interesting contributions to the study of primordial magnetic field.Comment: 17 pages, 3 figures, accepted for publication in PR

QCD Factorization for Quarkonium Production in Hadron Collions at Low Transverse Momentum

Inclusive production of a quarkonium $\eta_{c,b}$ in hadron collisions at low transverse momentum can be used to extract various Transverse-Momentum-Dependent(TMD) gluon distributions of hadrons, provided the TMD factorization for the process holds. The factorization involving unpolarized TMD gluon distributions of unpolarized hadrons has been examined with on-shell gluons at one-loop level. In this work we study the factorization at one-loop level with diagram approach in the most general case, where all TMD gluon distributions at leading twist are involved. We find that the factorization holds and the perturbative effects are represented by one perturbative coefficient. Since the initial gluons from hadrons are off-shell in general, there exists the so-called super-leading region found recently. We find that the contributions from this region can come from individual diagrams at one-loop level, but they are cancelled in the sum. Our factorized result for the differential cross-section is explicitly gauge-invariant.Comment: discussions and references are added. Published version on Phys. Rev.

Design of QMF (Quadrature Mirror Filter) in spatial domain and edge encoding

Simoncelli and Adelson have extended the one dimensional Quadrature Mirror Filter (QMF) to two dimensions with hexagon symmetry and three dimensional spatio-temporal extensions with rhombic-duodecahedray symmetry. Jain and Crochiere presented an excellent QMF design technique in the time domain. It is proposed to extend the design of a two dimensional QMF over a rectangular lattice in the spatial domain based primarily on the extension of the idea of Jain and Crochiere. In addition, the design will investigate the use of two dimensional Z-transformations. Since this proposed QMF is intended for the applications in image processing, all the important and interesting engineering issues will be addressed throughout the development phase. The design of a two dimensional QMF is discussed. The motivation is to achieve an extremely high data compression ratio. It is entirely possible to achieve dramatic results when pattern recognition techniques are employed. The final goal is the demonstration of extremely high data compression ratios using NASA pictures