2,911 research outputs found

    MSW mediated neutrino decay and the solar neutrino problem

    Get PDF
    We investigate the solar neutrino problem assuming simultaneous presence of MSW transitions in the sun and neutrino decay on the way from sun to earth. We do a global χ2\chi^2-analysis of the data on total rates in Cl, Ga and Superkamiokande (SK) experiments and the SK day-night spectrum data and determine the changes in the allowed region in the \dm - \tan^2\theta plane in presence of decay. We also discuss the implications for unstable neutrinos in the SNO experiment.Comment: Final version to appear in Phys. Rev.

    Spectroscopic investigation of unstudied southern PNe

    Full text link
    We present a spectroscopic investigation of two hitherto unstudied galactic planetary nebulae (MeWe 1-10 and MeWe 1-11) and one candidate object (MeWe 2-5). The candidate object clearly has been identified as a bipolar hourglass shaped PN. The galactic foreground extinction was derived and using photoionization models with CLOUDY the two round objects were classified as highly evolved nebulae.Comment: LaTeX, 5 pages with 6 figures, accepted in Astron. & Astrophy

    Morpho-kinematic analysis of the point-symmetric, bipolar planetary nebulae Hb 5 and K 3-17, a pathway to poly-polarity

    Full text link
    The kinematics of the bipolar planetary nebulae Hb~5 and K 3-17 are investigated in detail by means of a comprehensive set of spatially resolved high spectral resolution, long-slit spectra. Both objects share particularly interesting characteristics, such as a complex filamentary, rosette-type nucleus, axial point-symmetry and very fast bipolar outflows. The kinematic information of Hb~5 is combined with {\it HST} imagery to construct a detailed 3D model of the nebula using the code SHAPE. The model shows that the large scale lobes are growing in a non-homologous way. The filamentary loops in the core are proven to actually be secondary lobes emerging from what appears to be a randomly punctured, dense, gaseous core and the material that forms the point symmetric structure flows within the lobes with a distinct kinematic pattern and its interaction with the lobes has had a shaping effect on them. Hb~5 and K~3-17 may represent a class of fast evolving planetary nebulae that will develop poly-polar characteristics once the nebular core evolves and expands.Comment: 19 pages, 8 figures. To appear in The Astrophysical Journa

    The Classification of M1-78

    Full text link
    The published properties of M1-78 are discussed with the purpose to resolve the object's classification as either a planetary nebula or an ultracompact HII region. A classification as a planetary nebula is rejected primarily because of the high luminosity of the object, but because of the chemical composition and expansion velocity of the nebula, a novel classification is proposed instead: that of an ultracompact HII region with a post-main sequence central star (possibly a WN star). It must therefore follow that observable ultracompact HII regions persist beyond the main sequence lifetimes of at least some massive stars, and so cannot be transient phenomena that are seen only during pre-main sequence or early main sequence evolution.Comment: 16 pages, Postscrip

    Two body non-leptonic Λb\Lambda_b decays in quark model with factorization ansatz

    Full text link
    The two body non-leptonic Λb\Lambda_b decays are analyzed in factorization approximation, using quark model, ξ=1/Nc\xi = 1 / N_c as a free parameter. It is shown that the experimental branching ratio for ΛbΛJ/ψ\Lambda_b \longrightarrow \Lambda {J/\psi} restricts ξ\xi and this ratio can be understood for a value of ξ\xi which lies in the range 0ξ0.5 0 \leq \xi \leq 0.5 suggested by two body B meson decays. The branching ratios for ΛbΛcDs(Ds)\Lambda_b \longrightarrow \Lambda_{c} D^*_s(D_s) are predicted to be larger than the previous estimates. Finally it is pointed that CKM-Wolfenstein parameter ρ2+η2\rho^2 + \eta^2, where η\eta is CP phase, can be determined from the ratio of widths of ΛbΛDˉ\Lambda_b \longrightarrow \Lambda \bar{D} and ΛbΛJ/ψ\Lambda_b \longrightarrow \Lambda {J/\psi} or that of ΛbpDs\Lambda_b \longrightarrow p D_s and ΛbΛcDs\Lambda_b \longrightarrow \Lambda_c D_s independent of the parameter ξ\xi.Comment: 18 pages, latex, 1 figure available on request, please send any questions or comments to [email protected]

    Chargino Production at an e-e- Collider

    Get PDF
    The chargino pair production in eee^-e^- collisions with their subsequent decays are considered within SUSY models with R-parity violation and with lepton number non-conservation. The production process (s=1\sqrt{s}=1 TeV) is predicted to be large in a wide range of both sneutrino and chargino masses. The influence of all virtual sneutrino states and their mixings with electrons are taken into account. Some specific situations are pointed out when significant suppressions of the cross section can take place. The chargino decays are discussed for either the chargino as LSP or the chargino as heavier sparticle. In both cases unique signals are possible with up to six charged fermions and without missing energy.Comment: 9 page

    K_L \ra \mu^\pm e^\mp \nu \overline{\nu} as background to K_L \ra \mu^\pm e^\mp

    Full text link
    We consider the process K_L \ra \mu^\pm e^\mp \nu \overline{\nu} at next to leading order in chiral perturbation theory. This process occurs in the standard model at second order in the weak interaction and constitutes a potential background in searches for new physics through the modes K_L \ra \mu^\pm e^\mp. We find that the same cut, Mμe>489M_{\mu e}>489~MeV, used to remove the sequential decays K_{l3}\ra \pi_{l2} pushes the B(K_L \ra \mu^\pm e^\mp \nu \overline{\nu}) to the 102310^{-23} level, effectively removing it as a background.Comment: 8 pages, LaTeX, 1 figure appended as postscript file after \end{document}. Fermilab-Pub-93/024-
    corecore