Non-decoupling Effects of Heavy Particles in Triple Gauge Boson Vertices

Non-decoupling effects of heavy particles present in beyond-the-standard models are studied for the triple gauge boson vertices $\gamma W^+W^-$ and $Z^0W^+W^-$. We show from a general argument that the non-decoupling effects are described by four independent parameters, in comparison with the three parameters $S$, $T$ and $U$ in the oblique corrections. These four parameters of the effective triple gauge boson vertices are computed in two beyond-the-standard models. We also study the relation of the four parameters to the $S$, $T$, $U$ parameters, relying on an operator analysis.Comment: 13 pages, plain tex using PHYZZX macropackag

Mössbauer study of nanodimensional nickel ferrite-mechanochemical synthesis and catalytic properties

Iron-nickel spinel oxide NiFe2O4 nanoparticles have been prepared by the combination of chemical precipitation and subsequent mechanical milling. For comparison, their analogue obtained by thermal synthesis is also studied. Phase composition and structural properties of iron-nickel oxides are investigated by X-ray diffraction and Mössbauer spectroscopy. Their catalytic behavior in methanol decomposition to CO and methane is tested. An influence of the preparation method on the reduction and catalytic properties of iron-nickel samples is established

Synthesis and search for superconductivity in LiBC

Following the recent theoretical prediction of superconductivity in hole doped LiBC by Rosner et al [1], we have attempted to synthesise Li deficient LixBC (x = 1, 0.8, 0.6 and 0.4) and look for superconductivity in this system. Our synthesis procedure, following the recipe for MgB2, involves reaction of elemental components in a Ta crucible at 900o C under 50 bar of argon pressure. X-ray diffraction measurements indicate the formation of P63/mmc structure up to x=0.6. However, no diamagnetic signal or zero resistance, corresponding to the superconducting transition, was observed in the temperature range of 300 to 4 K. This is possibly related to the presence of disorder in the B-C stacking; evidence for which is suggested from a study of the vibrational modes of LixBC through infrared spectroscopy.Comment: 7 pages, 6 figures 1 tabl

Bethe ansatz for the XXX-S chain with non-diagonal open boundaries

We consider the algebraic Bethe ansatz solution of the integrable and isotropic XXX-S Heisenberg chain with non-diagonal open boundaries. We show that the corresponding K-matrices are similar to diagonal matrices with the help of suitable transformations independent of the spectral parameter. When the boundary parameters satisfy certain constraints we are able to formulate the diagonalization of the associated double-row transfer matrix by means of the quantum inverse scattering method. This allows us to derive explicit expressions for the eigenvalues and the corresponding Bethe ansatz equations. We also present evidences that the eigenvectors can be build up in terms of multiparticle states for arbitrary S.Comment: 62 page

Anisotropic Optic Conductivities due to Spin and Orbital Orderings in LaVO3 and YVO3: First-Principles Studies

The anisotropy of low energy (0$\sim$5eV) optical excitations in strongly correlated transition-metal oxides is closely related to the spin and orbital orderings. The recent successes of LDA+$U$ method in describing the magnetic and electronic structures enable us to calculate the optical conductivity from first-principles. The LaVO$_3$ and YVO$_3$, both of which have $3d^2$ configuration and have various spin and orbital ordered phases at low temperature, show distinct anisotropy in the optical spectra. The effects of spin and orbital ordering on the anisotropy are studied in detail based on our first-principles calculations. The experimental spectra of both compounds at low temperature phases can be qualitatively explained with our calculations, while the studies for the intermediate temperature phase of YVO$_3$ suggest the substantial persistence of the low temperature phase at elevated temperature.Comment: 6 pages, 3 figures, accepted by PR

Toward closing rice telomere gaps: mapping and sequence characterization of rice subtelomere regions.

Despite the collective efforts of the international community to sequence the complete rice genome, telomeric regions of most chromosome arms remain uncharacterized. In this report we present sequence data from subtelomere regions obtained by analyzing telomeric clones from two 8.8 × genome equivalent 10-kb libraries derived from partial restriction digestion with HaeIII or Sau3AI (OSJNPb HaeIII and OSJNPc Sau3AI). Seven telomere clones were identified and contain 25¿100 copies of the telomere repeat (CCCTAAA)n on one end and unique sequences on the opposite end. Polymorphic sequence-tagged site markers from five clones and one additional PCR product were genetically mapped on the ends of chromosome arms 2S, 5L, 10S, 10L, 7L, and 7S. We found distinct chromosome-specific telomere-associated tandem repeats (TATR) on chromosome 7 (TATR7) and on the short arm of chromosome 10 (TATR10s) that showed no significant homology to any International Rice Genome Sequencing Project (IRGSP) genomic sequence. The TATR7, a degenerate tandem repeat which is interrupted by transposable elements, appeared on both ends of chromosome 7. The TATR10s was found to contain an inverted array of three tandem repeats displaying an interesting secondary folding pattern that resembles a telomere loop (t-loop) and which may be involved in a protective function against chromosomal end degradatio

Neutrino Masses with "Zero Sum" Condition: mν1+mν2+mν3=0m_{\nu_1} + m_{\nu_2} + m_{\nu_3} = 0

It is well known that the neutrino mass matrix contains more parameters than experimentalists can hope to measure in the foreseeable future even if we impose CP invariance. Thus, various authors have proposed ansatzes to restrict the form of the neutrino mass matrix further. Here we propose that $m_{\nu_1} + m_{\nu_2} + m_{\nu_3} = 0$; this ``zero sum'' condition can occur in certain class of models, such as models whose neutrino mass matrix can be expressed as commutator of two matrices. With this condition, the absolute neutrino mass can be obtained in terms of the mass-squared differences. When combined with the accumulated experimental data this condition predicts two types of mass hierarchies, with one of them characterized by $m_{\nu_3} \approx -2m_{\nu_1} \approx -2 m_{\nu_2} \approx 0.063$ eV, and the other by $m_{\nu_1} \approx -m_{\nu_2} \approx 0.054$ eV and $m_{\nu_3} \approx 0.0064$ eV. The mass ranges predicted is just below the cosmological upper bound of 0.23 eV from recent WMAP data and can be probed in the near future. We also point out some implications for direct laboratory measurement of neutrino masses, and the neutrino mass matrix.Comment: Latex 12 pages. No figures. New references adde

Measurement of the Branching Fraction for B->eta' K and Search for B->eta'pi+

We report measurements for two-body charmless B decays with an eta' meson in the final state. Using 11.1X10^6 BBbar pairs collected with the Belle detector, we find BF(B^+ ->eta'K^+)=(79^+12_-11 +-9)x10^-6 and BF(B^0 -> eta'K^0)=(55^+19_-16 +-8)x10^-6, where the first and second errors are statistical and systematic, respectively. No signal is observed in the mode B^+ -> eta' pi^+, and we set a 90% confidence level upper limit of BF(B^+-> eta'pi^+) eta'K^+- decays is investigated and a limit at 90% confidence level of -0.20<Acp<0.32 is obtained.Comment: Submitted to Physics Letters

Observation of Cabibbo-suppressed and W-exchange Lambda_c^+ baryon decays

We present measurements of the Cabibbo-suppressed decays Lambda_c^+ --> Lambda0 K+ and Lambda_c^+ --> Sigma0 K+ (both first observations), Lambda_c^+ --> Sigma+ K+ pi- (seen with large statistics for the first time), Lambda_c^+ --> p K+ K- and Lambda_c^+ --> p phi (measured with improved accuracy). Improved branching ratio measurements for the decays Lambda_c^+ --> Sigma+ K+ K- and Lambda_c^+ --> Sigma+ phi, which are attributed to W-exchange diagrams, are shown. We also present the first evidence for Lambda_c^+ --> Xi(1690)^0 K+ and set an upper limit on the non-resonant decay Lambda_c^+ --> Sigma+ K+ K-. This analysis was performed using 32.6 fb^{-1} of data collected by the Belle detector at the asymmetric e+ e- collider KEKB.Comment: Submitted to Phys. Lett. B. v2: A small correction to the Authorlist was made. An earlier version of this analysis was released as BELLE-CONF-0130, hep-ex/010800