2,678 research outputs found

    Final results of nu-e-bar electron scattering cross-section measurements and constraints on new physics

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    The nu-e-bar electron elastic scattering cross-section was measured with a CsI(Tl) scintillating crystal detector array with a total mass of 187 kg at the Kuo-Sheng Nuclear Power Station. The detectors were exposed to a reactor nu-e-bar flux of 6.4 X 10^{12} cm^{-2}s^{-1} originated from a core with 2.9 GW thermal power. Using 29882/7369 kg-days of Reactor ON/OFF data, the Standard Model (SM) of electroweak interaction was probed at the 4-momentum transfer range of Q^2 ~ 3 X 10^{-6} GeV^2. A cross-section ratio of R_{expt} = [1.08 +- 0.21(stat) +- 0.16(sys)] X R_{SM} was measured. Constraints on the electroweak parameters (g_V,g_A) were placed, corresponding to a weak mixing angle measurement of \s2tw = [0.251 +- 0.031(stat) +- 0.024(sys)]. Destructive interference in the SM nu-e-bar+e processes was verified. Bounds on neutrino anomalous electromagnetic properties (neutrino magnetic moment and neutrino charge radius), non-standard neutrino interactions, upparticle physics and non-commutative physics were placed. We summarize the experimental details and results, and discuss projected sensitivities with realistic and feasible hardware upgrades.Comment: 4 pages, 4 figures, 2 tables ; To appear in Proceedings of TAUP-2011 Conferenc

    Neutrino Experiments : Highlights

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    This article consists of two parts. The first section presents the highlights on the goals of neutrino physics, status of the current neutrino experiments and future directions and program. The second section describes the theme, program and research efforts for the TEXONO Collaboration among scientists from Taiwan and China.Comment: 7 pages, 7 figure; Invited Contributions to the Proceedings of ``The Fifth International Workshop on Particle Physics Phenomenology (PPP2000)'

    The LyAlpha Line Profiles of Ultraluminous Infrared Galaxies: Fast Winds and Lyman Continuum Leakage

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    We present new Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet (far-UV) spectroscopy and Keck Echellete optical spectroscopy of 11 ultraluminous infrared galaxies (ULIRGs), a rare population of local galaxies experiencing massive gas inflows, extreme starbursts, and prominent outflows. We detect H Lyman alpha emission from 8 ULIRGs and the companion to IRAS09583+4714. In contrast to the P Cygni profiles often seen in galaxy spectra, the H Lyman alpha profiles exhibit prominent, blueshifted emission out to Doppler shifts exceeding -1000 km/s in three HII-dominated and two AGN-dominated ULIRGs. To better understand the role of resonance scattering in shaping the H Lyman alpha line profiles, we directly compare them to non-resonant emission lines in optical spectra. We find that the line wings are already present in the intrinsic nebular spectra, and scattering merely enhances the wings relative to the line core. The H Lyman alpha attenuation (as measured in the COS aperture) ranges from that of the far-UV continuum to over 100 times more. A simple radiative transfer model suggests the H Lyman alpha photons escape through cavities which have low column densities of neutral hydrogen and become optically thin to the Lyman continuum in the most advanced mergers. We show that the properties of the highly blueshifted line wings on the H Lyman alpha and optical emission-line profiles are consistent with emission from clumps of gas condensing out of a fast, hot wind. The luminosity of the H Lyman alpha emission increases non-linearly with the ULIRG bolometric luminosity and represents about 0.1 to 1% of the radiative cooling from the hot winds in the HII-dominated ULIRGs.Comment: Submitted to Ap

    Psychosocial perception of adults with onychomycosis: a blinded, controlled comparison of 1,017 adult Hong Kong residents with or without onychomycosis

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    BACKGROUND: A survey was conducted amongst 1,017 Hong Kong residents ages 18 and over to determine their knowledge of fungal nail infections (onychomycosis) and the psychosocial impact of the disease on the relationships, social lives and careers of sufferers. METHODS: The Fungal Nail Perception Survey was conducted by email and online between May 29th and June 10th, 2013. Participants were shown three photographs of people with and without onychomycosis of the toenails. Respondents were asked ten questions (repeated for each picture) to ascertain their perceptions of the people in the pictures. Questions were related to perceptions around the ability of sufferers and non-sufferers to form relationships with others, social activities of sufferers and non-sufferers, perceptions of the effect of the disease on the potential for career success, and awareness of fungal nail disease and health. The sub-population who themselves suffered from onychomycosis were asked about self-perception as well as their perception of others with onychomycosis. RESULTS: Compared with non-sufferers, survey respondents perceived those with onychomycosis as less likely to be able to form good relationships. They also indicated that they would be more likely to exclude sufferers than non-sufferers from social activities and that they would be more likely to feel uncomfortable when sitting or standing beside an infected person than beside an uninfected person. Respondents perceived people with onychomycosis to be less able to perform well in their chosen career than with someone without onychomycosis. Interestingly, those respondents who themselves were infected felt socially excluded, upset and embarrassed by their infection. CONCLUSIONS: Onychomycosis may lead to stigmatization and social exclusion. Misconceptions of onychomycosis are high and education about the disease needs to be improved. Early recognition and treatment of the disease is essential to avoid complications and improve treatment outcomes, which would lead to reduced psychosocial impact on those with fungal nail infections

    Atomic ionization by sterile-to-active neutrino conversion and constraints on dark matter sterile neutrinos with germanium detectors

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    The transition magnetic moment of a sterile-to-active neutrino conversion gives rise to not only radiative decay of a sterile neutrino, but also its non-standard interaction (NSI) with matter. For sterile neutrinos of keV-mass as dark matter candidates, their decay signals are actively searched for in cosmic X-ray spectra. In this work, we consider the NSI that leads to atomic ionization, which can be detected by direct dark matter experiments. It is found that this inelastic scattering process for a nonrelativistic sterile neutrino has a pronounced enhancement in the differential cross section at energy transfer about half of its mass, manifesting experimentally as peaks in the measurable energy spectra. The enhancement effects gradually smear out as the sterile neutrino becomes relativistic. Using data taken with germanium detectors that have fine energy resolution in keV and sub-keV regimes, constraints on sterile neutrino mass and its transition magnetic moment are derived and compared with those from astrophysical observations

    Derivations of Atomic Ionization Effects Induced by Neutrino Magnetic Moments

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    A recent paper [M.B. Voloshin, Phys. Rev. Lett. 105, 201801 (2010)] pointed out that our earlier derivations of atomic ionization cross-section due to neutrino magnetic moments (arXiv:1001.2074v2) involved unjustified assumptions. We confirm and elaborate on this comment with these notes. We caution that the results of the sum-rule approach in this paper contradict the expected behaviour in atomic transitions.Comment: V3 3 pages ; confirm and elaborate on unjustified assumptions in V1 & V
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