Left-Handed Surface Waves in a Photonic Structure

It is demonstrated that an isotropic left-handed medium can be constructed as a photonic structure consisting of two dielectric materials, one with positive and another with negative dielectric permittivities epsilon. Electromagnetic waves supported by this structure are the surface waves localized at the dielectric interfaces. These surface waves can be either surface phonons or surface plasmons. Two examples of negative epsilon materials are used: silicon carbide and free-electron gas.Comment: 7 pages, two figure

Bose-Einstein correlations at the Z0Z^{0} peak

Presented here is an overview of studies of the manifestations of the Bose-Einstein correlations in the hadronic decays of Z/sup 0/ boson, performed by the LEP experiments. The scope of the overview is confined to studies of two and three particle correlation functions for charged pions, with emphasis on analyses of transverse mass m/sub T/ and directional dependence of the two particle correlation function parameters. (17 refs)

A Scale‐Aware Parameterization for Estimating Subgrid Variability of Downward Solar Radiation Using High‐Resolution Digital Elevation Model Data

AbstractSubgrid variability of solar downward radiation at the surface can be important in estimating subgrid variability of other radiation‐driven variables, such as snowmelt and soil temperature. However, this information is ignored in current hydrological and weather prediction models as only the mean downward solar radiation of model grid is used. In this study, a parameterization for estimating subgrid variability of downward solar radiation from the model grid mean using high‐resolution digital elevation model (DEM) data is proposed. This scheme considers aspect and slope effects on the subgrid variability. The advantage of this scheme is that computations are performed at the same resolution as the considered hydrological or weather prediction model, and subgrid topographic properties derived from high‐resolution DEM data are used as static inputs. This proposed scheme has been verified in mountainous and flat areas, respectively. It is found that the scheme can well estimate the subgrid variability of downward solar radiation. Also, effects of the DEM resolution on the calculated subgrid variability and the spatial correlation of downward solar radiation are studied. Results show that modeled subgrid variability highly depends on the resolution of the DEM, while the spatial correlation is negligibly time dependent. The proposed scheme can be used in any hydrological and weather prediction model to estimate subgrid variability of downward solar radiation. For example, it is planned to be tested in future NOAA regional and global weather models to account for the effects of the subgrid variability of downward solar radiation on the snow model of the land‐surface component

On the T-Odd Quark Fragmentation Function and on Transversal Handedness

The first probe of the correlation of the T-odd one-particle fragmentation function responsible for the left--right asymmetry of fragmentation of a transversely polarized quark is done by using the 1991-95 DELPHI data for $Z\to 2$-jet decay. Integrated over the fraction of longitudinal and transversal momenta, this correlation is of 1.5% order, which means order of 13% for the analyzing power. A rather large ($\approx 10$) handedness transversal to the production plane was observed in the diffractive production of ($\pi^-\pi^+\pi^-$) triples from nuclei by the $40 GeV/c \pi^-$--beam. It was shown that the phenomenon has a clear dynamic origin and resembles the single spin asymmetry behavior. All this makes us hope to use this effects in polarized DIS experiments for transversity measurement.Comment: 10 pp, 5 epsfig, Latex 2e, szjp.cls, epsfig.sty, wrapfig.sty included. Talk in "Spin and Symmetry - Praha98". To be published in Czechoslovak Journal of Physics, Supp