4,000 research outputs found

    Solar neutrino measurements using the full data period of Super-Kamiokande-IV

    No full text
    International audienceAn analysis of solar neutrino data from the fourth phase of Super-Kamiokande~(SK-IV) from October 2008 to May 2018 is performed and the results are presented. The observation time of the data set of SK-IV corresponds to 29702970~days and the total live time for all four phases is 58055805~days. For more precise solar neutrino measurements, several improvements are applied in this analysis: lowering the data acquisition threshold in May 2015, further reduction of the spallation background using neutron clustering events, precise energy reconstruction considering the time variation of the PMT gain. The observed number of solar neutrino events in 3.493.49--19.4919.49~MeV electron kinetic energy region during SK-IV is 65,443388+390(stat.)±925(syst.)65,443^{+390}_{-388}\,(\mathrm{stat.})\pm 925\,(\mathrm{syst.}) events. Corresponding 8B\mathrm{^{8}B} solar neutrino flux is (2.314±0.014(stat.)±0.040(syst.))×106 cm2s1(2.314 \pm 0.014\, \rm{(stat.)} \pm 0.040 \, \rm{(syst.)}) \times 10^{6}~\mathrm{cm^{-2}\,s^{-1}}, assuming a pure electron-neutrino flavor component without neutrino oscillations. The flux combined with all SK phases up to SK-IV is (2.336±0.011(stat.)±0.043(syst.))×106 cm2s1(2.336 \pm 0.011\, \rm{(stat.)} \pm 0.043 \, \rm{(syst.)}) \times 10^{6}~\mathrm{cm^{-2}\,s^{-1}}. Based on the neutrino oscillation analysis from all solar experiments, including the SK 58055805~days data set, the best-fit neutrino oscillation parameters are sin2θ12,solar=0.306±0.013\rm{sin^{2} \theta_{12,\,solar}} = 0.306 \pm 0.013 and Δm21,solar2=(6.100.81+0.95)×105 eV2\Delta m^{2}_{21,\,\mathrm{solar}} = (6.10^{+ 0.95}_{-0.81}) \times 10^{-5}~\rm{eV}^{2}, with a deviation of about 1.5σ\sigma from the Δm212\Delta m^{2}_{21} parameter obtained by KamLAND. The best-fit neutrino oscillation parameters obtained from all solar experiments and KamLAND are sin2θ12,global=0.307±0.012\sin^{2} \theta_{12,\,\mathrm{global}} = 0.307 \pm 0.012 and Δm21,global2=(7.500.18+0.19)×105 eV2\Delta m^{2}_{21,\,\mathrm{global}} = (7.50^{+ 0.19}_{-0.18}) \times 10^{-5}~\rm{eV}^{2}

    The DUNE Far Detector Vertical Drift Technology, Technical Design Report

    No full text
    International audienceDUNE is an international experiment dedicated to addressing some of the questions at the forefront of particle physics and astrophysics, including the mystifying preponderance of matter over antimatter in the early universe. The dual-site experiment will employ an intense neutrino beam focused on a near and a far detector as it aims to determine the neutrino mass hierarchy and to make high-precision measurements of the PMNS matrix parameters, including the CP-violating phase. It will also stand ready to observe supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector implements liquid argon time-projection chamber (LArTPC) technology, and combines the many tens-of-kiloton fiducial mass necessary for rare event searches with the sub-centimeter spatial resolution required to image those events with high precision. The addition of a photon detection system enhances physics capabilities for all DUNE physics drivers and opens prospects for further physics explorations. Given its size, the far detector will be implemented as a set of modules, with LArTPC designs that differ from one another as newer technologies arise. In the vertical drift LArTPC design, a horizontal cathode bisects the detector, creating two stacked drift volumes in which ionization charges drift towards anodes at either the top or bottom. The anodes are composed of perforated PCB layers with conductive strips, enabling reconstruction in 3D. Light-trap-style photon detection modules are placed both on the cryostat's side walls and on the central cathode where they are optically powered. This Technical Design Report describes in detail the technical implementations of each subsystem of this LArTPC that, together with the other far detector modules and the near detector, will enable DUNE to achieve its physics goals

    Solar neutrino measurements using the full data period of Super-Kamiokande-IV

    No full text
    International audienceAn analysis of solar neutrino data from the fourth phase of Super-Kamiokande~(SK-IV) from October 2008 to May 2018 is performed and the results are presented. The observation time of the data set of SK-IV corresponds to 29702970~days and the total live time for all four phases is 58055805~days. For more precise solar neutrino measurements, several improvements are applied in this analysis: lowering the data acquisition threshold in May 2015, further reduction of the spallation background using neutron clustering events, precise energy reconstruction considering the time variation of the PMT gain. The observed number of solar neutrino events in 3.493.49--19.4919.49~MeV electron kinetic energy region during SK-IV is 65,443388+390(stat.)±925(syst.)65,443^{+390}_{-388}\,(\mathrm{stat.})\pm 925\,(\mathrm{syst.}) events. Corresponding 8B\mathrm{^{8}B} solar neutrino flux is (2.314±0.014(stat.)±0.040(syst.))×106 cm2s1(2.314 \pm 0.014\, \rm{(stat.)} \pm 0.040 \, \rm{(syst.)}) \times 10^{6}~\mathrm{cm^{-2}\,s^{-1}}, assuming a pure electron-neutrino flavor component without neutrino oscillations. The flux combined with all SK phases up to SK-IV is (2.336±0.011(stat.)±0.043(syst.))×106 cm2s1(2.336 \pm 0.011\, \rm{(stat.)} \pm 0.043 \, \rm{(syst.)}) \times 10^{6}~\mathrm{cm^{-2}\,s^{-1}}. Based on the neutrino oscillation analysis from all solar experiments, including the SK 58055805~days data set, the best-fit neutrino oscillation parameters are sin2θ12,solar=0.306±0.013\rm{sin^{2} \theta_{12,\,solar}} = 0.306 \pm 0.013 and Δm21,solar2=(6.100.81+0.95)×105 eV2\Delta m^{2}_{21,\,\mathrm{solar}} = (6.10^{+ 0.95}_{-0.81}) \times 10^{-5}~\rm{eV}^{2}, with a deviation of about 1.5σ\sigma from the Δm212\Delta m^{2}_{21} parameter obtained by KamLAND. The best-fit neutrino oscillation parameters obtained from all solar experiments and KamLAND are sin2θ12,global=0.307±0.012\sin^{2} \theta_{12,\,\mathrm{global}} = 0.307 \pm 0.012 and Δm21,global2=(7.500.18+0.19)×105 eV2\Delta m^{2}_{21,\,\mathrm{global}} = (7.50^{+ 0.19}_{-0.18}) \times 10^{-5}~\rm{eV}^{2}

    The DUNE Far Detector Vertical Drift Technology, Technical Design Report

    No full text
    International audienceDUNE is an international experiment dedicated to addressing some of the questions at the forefront of particle physics and astrophysics, including the mystifying preponderance of matter over antimatter in the early universe. The dual-site experiment will employ an intense neutrino beam focused on a near and a far detector as it aims to determine the neutrino mass hierarchy and to make high-precision measurements of the PMNS matrix parameters, including the CP-violating phase. It will also stand ready to observe supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector implements liquid argon time-projection chamber (LArTPC) technology, and combines the many tens-of-kiloton fiducial mass necessary for rare event searches with the sub-centimeter spatial resolution required to image those events with high precision. The addition of a photon detection system enhances physics capabilities for all DUNE physics drivers and opens prospects for further physics explorations. Given its size, the far detector will be implemented as a set of modules, with LArTPC designs that differ from one another as newer technologies arise. In the vertical drift LArTPC design, a horizontal cathode bisects the detector, creating two stacked drift volumes in which ionization charges drift towards anodes at either the top or bottom. The anodes are composed of perforated PCB layers with conductive strips, enabling reconstruction in 3D. Light-trap-style photon detection modules are placed both on the cryostat's side walls and on the central cathode where they are optically powered. This Technical Design Report describes in detail the technical implementations of each subsystem of this LArTPC that, together with the other far detector modules and the near detector, will enable DUNE to achieve its physics goals

    The DUNE Far Detector Vertical Drift Technology, Technical Design Report