1,551 research outputs found

    MSW mediated neutrino decay and the solar neutrino problem

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    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.

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

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    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-

    The Lantern Vol. 13, No. 1, October 1944

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    • One Doctor\u27s Story • Sonnet for a Friend • Lines and a Sonnet • Chant • Circus Impressions • Spring Comes Latehttps://digitalcommons.ursinus.edu/lantern/1034/thumbnail.jp

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

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    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]

    Neutrino Decay as an Explanation of Atmospheric Neutrino Observations

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    We show that the observed zenith angle dependence of the atmospheric neutrinos can be accounted for by neutrino decay. Furthermore, it is possible to account for all neutrino anomalies with just three flavors.Comment: 4 pages, 1 figur

    Going places

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    Journeys. We all make them. Often they take us to exotic places. Sometimes they take us even further. They might take us through time. Or they might take us into a new way of life. There are times too, when we go all over the world and back again only to find that home is, after all, where it’s all happening. This book contains stories about many different types of journey. We hope you will enjoy travelling into it and finding a world that suits you

    Investigating on the nuclear obscuration in two types of Seyfert 2 galaxies

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    We build a large sample of Seyfert 2 galaxies (Sy2s) with both optical spectropolarimetric and X-ray data available, in which 29 Sy2s with the detection of polarized broad emission line (PBL) and 25 without. We find that for luminous Sy2s with L_[OIII] > 10^41 erg/s, sources with PBL have smaller X-ray absorption column density comparing with those without PBL (at 92.3% confidence level): most of the Sy2s with N_H<10^23.8 cm^-2 show PBL (86%, 12 out 14), while the fraction is much smaller for sources with heavier obscuration (54%, 15 out 28). The confidence level of the difference in absorption bounces up to 99.1% while using the "T" ratio (F_2-10keV/F_[O III]) as an indicator. We rule out observation or selection bias as the origin for the difference. Our results, for the first time with high statistical confidence, show that, in additional to the nuclei activity, the nuclear obscuration also plays an important role in the visibility of PBL in Sy2s. These results can be interpreted in the framework of the unified model. We can reach these results in the unified model if: a) the absorption column density is higher at large inclinations and b) the scattering region is obscured at large inclinations.Comment: 28 pages, including 7 figures and 3 tables, ApJ accepte

    Automated PGP9.5 immunofluorescence staining: a valuable tool in the assessment of small fiber neuropathy?

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    BACKGROUND: In this study we explored the possibility of automating the PGP9.5 immunofluorescence staining assay for the diagnosis of small fiber neuropathy using skin punch biopsies. The laboratory developed test (LDT) was subjected to a validation strategy as required by good laboratory practice guidelines and compared to the well-established gold standard method approved by the European Federation of Neurological Societies (EFNS). To facilitate automation, the use of thinner sections. (16 µm) was evaluated. Biopsies from previously published studies were used. The aim was to evaluate the diagnostic performance of the LDT compared to the gold standard. We focused on technical aspects to reach high-quality standardization of the PGP9.5 assay and finally evaluate its potential for use in large scale batch testing. RESULTS: We first studied linear nerve fiber densities in skin of healthy volunteers to establish reference ranges, and compared our LDT using the modifications to the EFNS counting rule to the gold standard in visualizing and quantifying the epidermal nerve fiber network. As the LDT requires the use of 16 µm tissue sections, a higher incidence of intra-epidermal nerve fiber fragments and a lower incidence of secondary branches were detected. Nevertheless, the LDT showed excellent concordance with the gold standard method. Next, the diagnostic performance and yield of the LDT were explored and challenged to the gold standard using skin punch biopsies of capsaicin treated subjects, and patients with diabetic polyneuropathy. The LDT reached good agreement with the gold standard in identifying small fiber neuropathy. The reduction of section thickness from 50 to 16 µm resulted in a significantly lower visualization of the three-dimensional epidermal nerve fiber network, as expected. However, the diagnostic performance of the LDT was adequate as characterized by a sensitivity and specificity of 80 and 64 %, respectively. CONCLUSIONS: This study, designed as a proof of principle, indicated that the LDT is an accurate, robust and automated assay, which adequately and reliably identifies patients presenting with small fiber neuropathy, and therefore has potential for use in large scale clinical studies
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