1,972 research outputs found

    Extracting W Boson Couplings from the e+e−e^{+}e^{-} Production of Four Leptons

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    We consider the processes e+e−→ℓ+ℓ′−ννˉ′e^{+}e^{-}\rightarrow \ell^{+} \ell^{\prime -}\nu \bar{\nu}^{\prime}, including all possible charged lepton combinations, with regard to measuring parameters characterizing the WW boson. We calculate at what level these processes can be used to measure anamolous triple-boson vertice coupling parameters for the cases of e+e−e^{+}e^{-} colliders at 500 GeVGeV and 1 TeVTeV center of mass energies.Comment: 13 pages,OCIP/C-93-

    Spin-Correlation Coefficients and Phase-Shift Analysis for p+3^3He Elastic Scattering

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    Angular Distributions for the target spin-dependent observables A0y_{0y}, Axx_{xx}, and Ayy_{yy} have been measured using polarized proton beams at several energies between 2 and 6 MeV and a spin-exchange optical pumping polarized 3^3He target. These measurements have been included in a global phase-shift analysis following that of George and Knutson, who reported two best-fit phase-shift solutions to the previous global p+3^3He elastic scattering database below 12 MeV. These new measurements, along with measurements of cross-section and beam-analyzing power made over a similar energy range by Fisher \textit{et al.}, allowed a single, unique solution to be obtained. The new measurements and phase-shifts are compared with theoretical calculations using realistic nucleon-nucleon potential models.Comment: Submitted to Phys. Rev.

    [Colored solutions of Yang-Baxter equation from representations of U_{q}gl(2)]

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    We study the Hopf algebra structure and the highest weight representation of a multiparameter version of Uqgl(2)U_{q}gl(2). The commutation relations as well as other Hopf algebra maps are explicitly given. We show that the multiparameter universal R{\cal R} matrix can be constructed directly as a quantum double intertwiner, without using Reshetikhin's transformation. An interesting feature automatically appears in the representation theory: it can be divided into two types, one for generic qq, the other for qq being a root of unity. When applying the representation theory to the multiparameter universal R{\cal R} matrix, the so called standard and nonstandard colored solutions R(μ,ν;μ′,ν′)R(\mu,\nu; {\mu}', {\nu}') of the Yang-Baxter equation is obtained.Comment: [14]pages, latex, no figure

    Globular Clusters in the dE,N galaxy NGC 3115 DW1: New Insights from Spectroscopy and HST Photometry

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    The properties of globular clusters in dwarf galaxies are key to understanding the formation of globular cluster systems, and in particular in verifying scenarios in which globular cluster systems of larger galaxies formed (at least partly) from the accretion of dwarf galaxies. Here, we revisit the globular cluster system of the dE,N galaxy NGC 3115 DW1 - a companion of the nearby S0 galaxy NGC 3115 - adding Keck/LRIS spectroscopy and HST/WFPC2 imaging to previous ground-based photometry. Spectra for seven globular clusters reveal normal abundance ratios with respect to the Milky Way and M31 clusters, as well as a relatively high mean metallicity ([Fe/H] = -1.0+/-0.1 dex). Crude kinematics indicate a high velocity dispersion within 10 kpc which could either be caused by dark matter dominated outer regions, or by the stripping of outer globular clusters by the nearby giant galaxy NGC 3115. The total galaxy mass out to 3 and 10 kpc lies between 10^10 and 10^11 solar masses and 2*10^10 and 4*10^11 solar masses, respectively, depending on the mass estimator used and the assumptions on cluster orbits and systemic velocity. The HST imaging allows measurement of sizes for two clusters, returning core radii around 2.0 pc, similar to the sizes observed in other galaxies. Spectroscopy allows an estimate of the degree of contamination by foreground stars or background galaxies for the previous ground-based photometry, but does not require a revision of previous results: NGC 3115 DW1 hosts around 60+/-20 clusters which corresponds to a specific frequency of 4.9+/-1.9, on the high end for massive dEs. Given its absolute magnitude (M_V=-17.7 mag) and the properties of its cluster system, NGC 3115 DW1 appears to be a transition between a luminous dE and low-luminosity E galaxy.Comment: 25 pages, 8 figures, accepted for publication in The Astronomical Journal, August 2000 issu

    Supersymmetric QCD flavor changing top quark decay

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    We present a detailed and complete calculation of the gluino and scalar quarks contribution to the flavour-changing top quark decay into a charm quark and a photon, gluon, or a Z boson within the minimal supersymmetric standard model including flavour changing gluino-quarks-scalar quarks couplings in the right-handed sector. We compare the results with the ones presented in an earlier paper where we considered flavour changing couplings only in the left-handed sector. We show that these new couplings have important consequences leading to a large enhancement when the mixing of the scalar partners of the left- and right-handed top quark is included. Furthermore CP violation in the flavour changing top quark decay will occur when a SUSY phase is taken into account.Comment: 14 pages, latex, 3 figure

    The 63^{63}Ni(n,γ\gamma) cross section measured with DANCE

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    The neutron capture cross section of the s-process branch nucleus 63^{63}Ni affects the abundances of other nuclei in its region, especially 63^{63}Cu and 64^{64}Zn. In order to determine the energy dependent neutron capture cross section in the astrophysical energy region, an experiment at the Los Alamos National Laboratory has been performed using the calorimetric 4π\pi BaF2_2 array DANCE. The (n,γ\gamma) cross section of 63^{63}Ni has been determined relative to the well known 197^{197}Au standard with uncertainties below 15%. Various 63^{63}Ni resonances have been identified based on the Q-value. Furthermore, the s-process sensitivity of the new values was analyzed with the new network calculation tool NETZ.Comment: 11 pages, 13 page

    The upper triangular solutions to the three-state constant quantum Yang-Baxter equation

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    In this article we present all nonsingular upper triangular solutions to the constant quantum Yang-Baxter equation Rj1j2k1k2Rk1j3l1k3Rk2k3l2l3=Rj2j3k2k3Rj1k3k1l3Rk1k2l1l2R_{j_1j_2}^{k_1k_2}R_{k_1j_3}^{l_1k_3}R_{k_2k_3}^{l_2l_3}= R_{j_2j_3}^{k_2k_3}R_{j_1k_3}^{k_1l_3}R_{k_1k_2}^{l_1l_2} in the three state case, i.e. all indices ranging from 1 to 3. The upper triangular ansatz implies 729 equations for 45 variables. Fortunately many of the equations turned out to be simple allowing us to start breaking the problem into smaller ones. In the end we had a total of 552 solutions, but many of them were either inherited from two-state solutions or subcases of others. The final list contains 35 nontrivial solutions, most of them new.Comment: 24 Pages in LaTe
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