13 research outputs found
Measurement of coherent production in low energy neutrino-Carbon scattering
We report the first measurement of the flux-averaged cross section for charged current coherent production on carbon for neutrino energies less than 1.5 GeV to a restricted final state phase space region in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso {\it et al.}, the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. This results contradicts the null results reported by K2K and SciBooNE in a similar neutrino energy region
The T2K experiment
The T2K experiment is a long baseline neutrino oscillation experiment. Its main goal is to measure the last unknown lepton sector mixing angle θ13 by observing νe appearance in a νμ beam. It also aims to make a precision measurement of the known oscillation parameters, and sin22θ23, via νμ disappearance studies. Other goals of the experiment include various neutrino cross-section measurements and sterile neutrino searches. The experiment uses an intense proton beam generated by the J-PARC accelerator in Tokai, Japan, and is composed of a neutrino beamline, a near detector complex (ND280), and a far detector (Super-Kamiokande) located 295 km away from J-PARC. This paper provides a comprehensive review of the instrumentation aspect of the T2K experiment and a summary of the vital information for each subsystem
Testing Non-Standard Interactions Between Solar Neutrinos and Quarks with Super-Kamiokande
Non-Standard Interactions (NSI) between neutrinos and matter affect the neutrino flavor oscillations. Due to the high matter density in the core of the Sun, solar neutrinos are suited to probe these interactions. Using the kton-yr exposure of Super-Kamiokande to B solar neutrinos, we search for the presence of NSI. Our data favors the presence of NSI with down quarks at 1.8, and with up quarks at 1.6, with the best fit NSI parameters being () = (-3.3, -3.1) for -quarks and () = (-2.5, -3.1) for -quarks. After combining with data from the Sudbury Neutrino Observatory and Borexino, the significance increases by 0.1
Neutron tagging following atmospheric neutrino events in a water Cherenkov detector
International audienceWe present the development of neutron-tagging techniques in Super-Kamiokande IV using a neural network analysis. The detection efficiency of neutron capture on hydrogen is estimated to be 26%, with a mis-tag rate of 0.016 per neutrino event. The uncertainty of the tagging efficiency is estimated to be 9.0%. Measurement of the tagging efficiency with data from an Americium-Beryllium calibration agrees with this value within 10%. The tagging procedure was performed on 3,244.4 days of SK-IV atmospheric neutrino data, identifying 18,091 neutrons in 26,473 neutrino events. The fitted neutron capture lifetime was measured as 218±9 μs
Neutron Tagging following Atmospheric Neutrino Events in a Water Cherenkov Detector
International audienceWe present the development of neutron-tagging techniques in Super-Kamiokande IV using a neural network analysis. The detection efficiency of neutron capture on hydrogen is estimated to be 26%, with a mis-tag rate of 0.016 per neutrino event. The uncertainty of the tagging efficiency is estimated to be 9.0%. Measurement of the tagging efficiency with data from an Americium-Beryllium calibration agrees with this value within 10%. The tagging procedure was performed on 3,244.4 days of SK-IV atmospheric neutrino data, identifying 18,091 neutrons in 26,473 neutrino events. The fitted neutron capture lifetime was measured as 218 \pm 9 \mu s
Solar neutrino measurements using the full data period of Super-Kamiokande-IV
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 ~days and the total live time for all four phases is ~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 --~MeV electron kinetic energy region during SK-IV is events. Corresponding solar neutrino flux is , assuming a pure electron-neutrino flavor component without neutrino oscillations. The flux combined with all SK phases up to SK-IV is . Based on the neutrino oscillation analysis from all solar experiments, including the SK ~days data set, the best-fit neutrino oscillation parameters are and , with a deviation of about 1.5 from the parameter obtained by KamLAND. The best-fit neutrino oscillation parameters obtained from all solar experiments and KamLAND are and
Beneficial effects of biochar to contaminated soils on the bioavailability of Cd, Pb and Zn and the biomass production of rapeseed (Brassica napus L.).
The observation of the recent electron neutrino appearance in a muon neutrino
beam and the high-precision measurement of the mixing angle have
led to a re-evaluation of the physics potential of the T2K long-baseline
neutrino oscillation experiment. Sensitivities are explored for CP violation in
neutrinos, non-maximal , the octant of , and
the mass hierarchy, in addition to the measurements of ,
, and , for various combinations of
-mode and -mode data-taking.
With an exposure of ~protons-on-target, T2K can achieve
1- resolution of 0.050(0.054) on and
on for 100\%(50\%)
neutrino beam mode running assuming and eV. T2K will have sensitivity to the
CP-violating phase at 90\% C.L. or better over a significant
range. For example, if is maximal (i.e
=) the range is
for normal hierarchy and for inverted
hierarchy. When T2K data is combined with data from the NOA experiment,
the region of oscillation parameter space where there is sensitivity to observe
a non-zero is substantially increased compared to if each
experiment is analyzed alone.Comment: 40 pages, 27 figures, accepted by PTE