Tau polarization effects in the CNGS tau-neutrino appearance experiments

We studied tau polarization effects on the decay distributions of tau produced in the CNGS tau-neutrino appearance experiments. We show that energy and angular distributions for the decay products in the laboratory frame are significantly affected by the tau polarization. Rather strong azimuthal asymmetry about the tau momentum axis is predicted, which may have observable consequences in experiments even with small statistics.Comment: 5 pages, 6 eps figures, espcrc2.sty; Proceedings of the 4th International Workshop on Neutrino-Nucleus Interactions in the Few GeV Region (NuInt05), September 26-29, 2005, Okayama, Japa

Photoemission Quasi-Particle Spectra of Sr2_2RuO4_4

Multi-band quasi-particle calculations based on perturbation theory and dynamical mean field methods show that the creation of a photoemission hole state in Sr$_2$RuO$_4$ is associated with a highly anisotropic self-energy. Since the narrow Ru-derived $d_{xz,yz}$ bands are more strongly distorted by Coulomb correlations than the wide $d_{xy}$ band, charge is partially transferred from $d_{xz,yz}$ to $d_{xy}$, thereby shifting the $d_{xy}$ van Hove singularity close to the Fermi level.Comment: 4 pages, to be published in PRB Rapid Com

Parity-Odd Asymmetries in W-Jet Events at the Tevatron

Parity-odd asymmetries in the decay angular distribution of a W boson produced with a hard jet in p\bar{p} collisions arise only from QCD rescattering effects. If observed, these asymmetries will provide a first demonstration that perturbative QCD calculation is valid for the absorptive part of scattering amplitudes. We propose a simple observable to measure these asymmetries and perform realistic Monte Carlo simulations at Tevatron energies. It is shown that the Tevatron Run-II should provide sufficient statistics to test the prediction.Comment: 4pages, 2figures, revtex, references and discussions added, version to appear in PRL, typo correcte

Room temperature ferromagnetic behavior in the hollandite-type titanium oxide

A hollandite-type K(x)Ti(8)O(16) polycrystalline sample has been prepared and studied by magnetization, resistivity and x-ray photoelectron spectroscopy (XPS). Room temperature ferromagnetic behavior is observed in the magnetic hysteresis measurement. The sample shows a semiconductive temperature dependence in the resistivity measurement. Analysis of the Ti 2p(3/2) core-level XPS spectrum indicates that the titanium ions have a mixed valence of Ti(4+) and Ti(3+). In addition, the valence band spectrum reveals that the 3d electrons tend to localize on Ti(3+) ions in the hollandite-type TiO(2) lattice. Also, analysis of the valence band spectrum shows that the prepared sample is a wide-gap oxide with a band gap of 3.6 eV. These results indicate that the present hollandite-type K(x)Ti(8)O(16) sample can be classified as a TiO(2)-based wide-gap semiconductor with Curie temperature above room temperature. Room temperature ferromagnetism (RTFM) decreases in the sample prepared under a strong reducing gas atmosphere, accompanied with the decrease in the resistivity. The results imply that the localized 3d electrons are responsible for the RTFM of the K(x)Ti(8)O(16) sample

Effects of agar on explant growth and callus formation in color morphs of Gracilaria domingensis (Kützing) Sonder ex Dickie (Gracilariales, Rhodophyta)

Os efeitos da concentração de ágar no crescimento de explantes e na formação de calos foram avaliados em culturas axênicas de gametófitos femininos de morfos de coloração verde e vermelha de Gracilaria domingensis (Kützing) Sonder ex Dickie. Culturas unialgáceas foram mantidas em água do mar esterilizada (30-32 ups) enriquecida com 25% da solução de von Stosch (VSES 25%), 22 ± 2 °C, fotoperíodo de 14 h, irradiância de 50-80 µmol de fótons m-2 s-1. Para a obtenção de explantes axênicos, segmentos apicais e intercalares dos dois morfos foram cultivados por 48 h em meio VSES 25% com adição de uma solução antibiótica e antifúngica, e submetidos a uma lavagem com uma solução de água do mar esterilizada com 0,5% de hipoclorito de sódio e 200 µL L-1 de detergente por 20 segundos. Para avaliar os efeitos da concentração de ágar, os segmentos axênicos foram inoculados em meio ASP 12-NTA com concentrações distintas de ágar que variaram de zero a 1%. A adição de ágar no meio inibiu o crescimento dos segmentos apicais de ambos os morfos, bem como o crescimento de segmentos intercalares do morfo verde. Observou-se uma tendência geral no crescimento dos explantes, onde a taxa de crescimento foi inversamente proporcional à concentração de ágar. A adição de ágar no meio induziu a formação de três tipos de calo, denominados conforme a região do explante onde se originaram: calo apical, calo basal e calo intermediário. As concentrações de 0,5% e 0,7% de ágar foram as concentrações ótimas para indução de calos basais e calos intermediários no morfo verde, respectivamente. A presença de ágar foi essencial para a formação de calos intermediários e apicais. Os resultados indicam que o ágar apresenta um papel na regulação dos processos morfogenéticos em morfos pigmentares de G. domingensis.The effects of agar concentrations on growth and callus formation were studied in axenic cultures of female gametophytes of green and red morphs of Gracilaria domingensis (Kützing) Sonder ex Dickie. Unialgal cultures of both color morphs were maintained in sterilized seawater (30-32 psu) enriched with a quarter-strength of von Stosch’s solution (VSES 25%), 22 ± 2 ºC, photoperiod of 14 h, irradiance of 50-80 µmol photons m-2 s-1. To obtain axenic explants, apical and intercalary segments of the green and red morphs were cultured for 48 h in VSES 25% medium with addition of antifungal and antibiotic solution, washed with a solution of sterile seawater with 0.5% of sodium hypochlorite and 200 µL L-1 of detergent during 20 seconds. In order to evaluate the effects of agar, apical and intercalary segments were inoculated into modified ASP 12-NTA synthetic medium with agar concentrations ranging from zero to 1.0%. Addition of agar to the culture medium inhibited the growth of apical segments of both morphs as well as the growth of intercalary segments of green morph. In general, growth rates of thallus segments were inversely proportional to agar concentration. Treatments with agar induced the formation of three types of callus, denominated in accordance with the explant region which gave rise to the callus: apical, basal, and intermediate calluses. Moreover, presence of agar is essential to induce intermediate and apical calluses. Concentrations of 0.5% and 0.7% of agar were the optimal values for the induction of basal and intermediate calluses of greem morph, respectively. The results indicated that agar has a regulatory role on morphogenetical processes in color morphs of G. domingensis

Vortices with fractional flux in two-gap superconductors and in extended Faddeev model

We discuss vortices allowed in two-gap superconductors, bilayer systems and in equivalent extended Faddeev model. We show that in these systems there exist vortices which carry an arbitrary fraction of magnetic flux quantum. Besides that we discuss topological defects which do not carry magnetic flux and describe features of ordinary one-magnetic-flux-quantum vortices in the two-gap system. The results should be relevant for the newly discovered two-band superconductor $Mg B_2$.Comment: v2 references added, v3 journal version, presentation improved. Links to related papers are available at the home page of the author http://www.teorfys.uu.se/PEOPLE/ego

Planning the Future of U.S. Particle Physics (Snowmass 2013): Chapter 6: Accelerator Capabilities

These reports present the results of the 2013 Community Summer Study of the APS Division of Particles and Fields ("Snowmass 2013") on the future program of particle physics in the U.S. Chapter 6, on Accelerator Capabilities, discusses the future progress of accelerator technology, including issues for high-energy hadron and lepton colliders, high-intensity beams, electron-ion colliders, and necessary R&D for future accelerator technologies.Comment: 26 page

Determination of the local structure of Sr2−x_{2-x}Mx_xIrO4_4 (M = K, La) as a function of doping and temperature

The local structure of correlated spin-orbit insulator Sr$_{2-x}$M$_x$IrO$_4$ (M = K, La) has been investigated by Ir L$_3$-edge extended x-ray absorption fine structure measurements. The measurements were performed as a function of temperature for different dopings induced by substitution of Sr with La or K. It is found that Ir-O bonds have strong covalency and they hardly show any change across the N\'eel temperature. In the studied doping range, neither Ir-O bonds nor their dynamics, measured by their mean square relative displacements, show any appreciable change upon carrier doping, indicating possibility of a nanoscale phase separation in the doped system. On the other hand, there is a large increase of the static disorder in Ir-Sr correlation, larger for K doping than La doping. Similarities and differences with respect to the local lattice displacements in cuprates are briefly discussed.Comment: Main text: 6 pages, 4 figures, Supplemental information: 2 pages, 2 figure