1,108 research outputs found

    Mixing among light scalar mesons and L=1 q\bar{q} scalar mesons

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    Following the re-establishment of the \sigma(600) and the \kappa(900), the light scalar mesons a_0(980) and f_0(980) together with the \sigma(600) and the \kappa(900) are considered as the chiral scalar partner of pseudoscalar nonet in SU(3) chiral symmetry, and the high mass scalar mesons a_0(1450), K^*_0(1430), f_0(1370) and f_0(1710) turned out to be considered as the L=1 q\bar{q} scalar mesons. We assume that the high mass of the L=1 q\bar{q} scalar mesons is caused by the mixing with the light scalar mesons. For the structure of the light scalar mesons, we adopted the qq\bar{q}\bar{q} model in order to explain the "scalar meson puzzle". The inter-mixing between the light scalar nonet and the high mass L=1 q\bar{q} nonet and the intra-mixing among each nonet are analyzed by including the glueball into the high mass scalar nonet.Comment: 16 pages, 5 figure

    Effects to Scalar Meson Decays of Strong Mixing between Low and High Mass Scalar Mesons

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    We analyze the mass spectroscopy of low and high mass scalar mesons and get the result that the coupling strengths of the mixing between low and high mass scalar mesons are very strong and the strengths of mixing for I=1,1/2I=1, 1/2 scalar mesons and those of I=0 scalar mesons are almost same. Next, we analyze the decay widths and decay ratios of these mesons and get the results that the coupling constants Aâ€ČA' for I=1,1/2I=1, 1/2 which represents the coupling of high mass scalar meson Nâ€ČN' -> two pseudoscalar mesons PPPP are almost same as the coupling Aâ€ČA' for the I=0. On the other hand, the coupling constant AA for I=1,I=1/2I=1, I=1/2 which represents the low mass scalar meson NN -> PPPP are far from the coupling constant AA for I=0. We consider a resolution for this discrepancy. Coupling constant Aâ€Čâ€ČA'' for glueball GG -> PPPP is smaller than the coupling Aâ€ČA'. ΞP\theta_P is 40∘∌50∘40^\circ \sim 50^\circ.Comment: 15 pages, 6 figure

    The Cr Isotopic Composition of Phosphates in IIIB Iron Meteorites: A Search for ^(53)Mn

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    The metal phases of iron meteorites contain excess ^(107) Ag most plausibly derived from the in situ decay of ^(107)Pd (T_(1/2) = 6.5 x 10^6y) (Kaiser and Wasserburg, 1983; Chen and Wasserburg, 1983). The Ag isotopic data suggest that diverse types of iron meteorites, including the Type IIIABs, usually associated with fractional crystallization and core formation in planetesimals, formed and cooled to - 600°C within - 10^7y of ^(107)Pd production

    Small Scale Anisotropy Predictions for the Auger Observatory

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    We study the small scale anisotropy signal expected at the Pierre Auger Observatory in the next 1, 5, 10, and 15 years of operation, from sources of ultra-high energy (UHE) protons. We numerically propagate UHE protons over cosmological distances using an injection spectrum and normalization that fits current data up to \sim 10^{20}\eV. We characterize possible sources of ultra-high energy cosmic rays (UHECRs) by their mean density in the local Universe, ρˉ=10−r\bar{\rho} = 10^{-r} Mpc−3^{-3}, with rr between 3 and 6. These densities span a wide range of extragalactic sites for UHECR sources, from common to rare galaxies or even clusters of galaxies. We simulate 100 realizations for each model and calculate the two point correlation function for events with energies above 4 \times 10^{19}\eV and above 10^{20}\eV, as specialized to the case of the Auger telescope. We find that for r\ga 4, Auger should be able to detect small scale anisotropies in the near future. Distinguishing between different source densities based on cosmic ray data alone will be more challenging than detecting a departure from isotropy and is likely to require larger statistics of events. Combining the angular distribution studies with the spectral shape around the GZK feature will also help distinguish between different source scenarios.Comment: 15 pages, 6 figures, 6 tables, submitted to JCA

    SU(3) Mixing for Excited Mesons

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    The SU(3)-flavor symmetry breaking and the quark-antiquark annihilation mechanism are taken into account for describing the singlet-octet mixing for several nonets assigned by Particle Data Group(PDG). This task is approached with the mass matrix formalism

    A Petrographic and MG Isotopic Study of CAI in BALI (C3V) and Coolidge (C4V)

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    One of the least well understood and most controversial aspects of CAI is the degree to which their mineralogical, chemical and isotopic composition has been affected by alteration and metamorphism. Coolidge is a highly metamorphosed carbonaceous chondrite, the only C4V (Van Schmus, 1969) and we have begun a petrographic and Mg isotopic study of Coolidge CAI to investigate the extent of chemical and isotopic reequilibration during thermal metamorphism. We also present the first Mg isotopic results from a coarse-grained CAI from Bali (C3V)

    Extension of the Cosmic-Ray Energy Spectrum Beyond the Predicted Greisen-Zatsepin-Kuz'min Cutoff

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    The cosmic-ray energy spectrum above 10^{18.5} eV is reported using the updated data set of the Akeno Giant Air Shower Array (AGASA) from February 1990 to October 1997. The energy spectrum extends beyond 10^{20} eV and the energy gap between the highest energy event and the others is being filled up with recently observed events. The spectral shape suggests the absence of the 2.7 K cutoff in the energy spectrum or a possible presence of a new component beyond the 2.7 K cutoff.Comment: to be published in PRL, 3 figures, REVTEX forma

    A Light Sterile Neutrino in the TopFlavor Model

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    A scenario based on the TopFlavor model is presented to explain the origin of a light sterile neutrino as indicated by all combined neutrino oscillation experiments. The model is phenomenologically well motivated and compatible with all available low-energy data. The derived nuetrino mass matrix can qualitatively explain the observed hierarchy in the neutrino mass splittings as indicated by the neutrino oscillation data. Numerical results are obtained for special cases.Comment: Plain Latex file, 12 page
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