Научная группа: T2K Collaboration
Загружается...
Участники
Funders
ID
Авторы
Публикации
Публикация
Только метаданные
Search for light sterile neutrinos with the T2K far detector Super-Kamiokande at a baseline of 295 km
(2019) Abe, K.; Akutsu, R.; Ali, A.; Andreopoulos, C.; Kudenko, Y.; Куденко, Юрий Григорьевич
We perform a search for light sterile neutrinos using the data from the T2K far detector at a baseline of 295 km, with an exposure of 14.7(7.6) x 10(20) protons on target in neutrino (antineutrino) mode. A selection of neutral-current interaction samples is also used to enhance the sensitivity to sterile mixing. No evidence of sterile neutrino mixing in the 3 + 1 model was found from a simultaneous fit to the charged-current muon, electron and neutral-current neutrino samples. We set the most stringent limit on the sterile oscillation amplitude sin(2)theta(24 )for the sterile neutrino mass splitting Delta m(41)(2 )< 3 x 10(-3 )eV(2)/c(4).
Публикация
Только метаданные
Search for heavy neutrinos with the T2K near detector ND280
(2019) Abe, K.; Akutsu, R.; Ali, A.; Andreopoulos, C.; Nishikawa, K.; Yamada, Y.
This paper reports on the search for heavy neutrinos with masses in the range 140 < M-N < 493 MeV/c(2) using the off-axis near detector ND280 of the T2K experiment. These particles can be produced from kaon decays in the standard neutrino beam and then subsequently decay in ND280. The decay modes under consideration are N -> l(alpha)(+/-)pi(-/+) and N -> l(alpha)(+)l(beta)nu (-(-))= (alpha, beta = e, mu). A search for such events has been made using the Time Projection Chambers of ND280, where the background has been reduced to less than two events in the current dataset in all channels. No excess has been observed in the signal region. A combined Bayesian statistical approach has been applied to extract upper limits on the mixing elements of heavy neutrinos to electron-, muon- and tau- flavored currents (U-e(2), U-mu(2), U-tau(2)) as a function of the heavy neutrino mass, e.g., U-e(2) < 10(-9) at 90% C.L. for a mass of 390 MeV/c(2). These constraints are competitive with previous experiments.
Публикация
Только метаданные
Measurement of neutrino and antineutrino neutral-current quasielasticlike interactions on oxygen by detecting nuclear deexcitation gamma rays
(2019) Abe, K.; Akutsu, R.; Ali, A.; Alt, C.; Kudenko, Y.; Куденко, Юрий Григорьевич
Neutrino- and antineutrino-oxygen neutral-current quasielasticlike interactions are measured at Super-Kamiokande using nuclear deexcitation gamma rays to identify signal-like interactions in data from a 14.94(16.35) x 10(20) protons-on-target exposure of the T2K neutrino (antineutrino) beam. The measured flux-averaged cross sections on oxygen nuclei are = 1.70 +/- 0.17(stat.)(-0.38)(+0.51) (syst.) x 10(-38) cm(2)/oxygen with a flux-averaged energy of 0.82 GeV and = 0.98 +/- 0.16(stat.)(-0.19)(+0.26)(syst.) x 10(-38)cm(2)/oxygen with a flux-averaged energy of 0.68 GeV, for neutrinos and antineutrinos, respectively. These results are the most precise to date, and the antineutrino result is the first cross section measurement of this channel. They are compared with various theoretical predictions. The impact on evaluation of backgrounds to searches for supernova relic neutrinos at present and future water Cherenkov detectors is also discussed.
Публикация
Только метаданные
Search for neutral-current induced single photon production at the ND280 near detector in T2K
(2019) Abe, K.; Akutsu, R.; Ali, A.; Andreopoulos, C.; Kudenko, Y.; Куденко, Юрий Григорьевич
© 2019 Institute of Physics Publishing. All rights reserved.Neutrino neutral-current (NC) induced single photon production is a subleading order process for accelerator-based neutrino beam experiments including T2K. It is, however, an important process to understand because it is a background for electron (anti)neutrino appearance oscillation experiments. Here, we performed the first search of this process below 1 GeV using the finegrained detector at the T2K ND280 off-axis near detector. By reconstructing single photon kinematics from electron positron pairs, we achieved 95% pure gamma ray sample from 5.738 1020 protons-on-targets neutrino mode data. We do not find positive evidence of NC induced single photon production in this sample. We set the model-dependent upper limit on the cross-section for this process, at 0.114 10-38 cm2 (90% C.L.) per nucleon, using the J-PARC off-axis neutrino beam with an average energy of .En. ~ 0.6 GeV. This is the first limit on this process below 1.GeV which is important for current and future oscillation experiments looking for electron neutrino appearance oscillation signals.
Публикация
Только метаданные
Measurement of the muon neutrino charged-current single pi(+) production on hydrocarbon using the T2K off-axis near detector ND280
(2020) Abe, K.; Akutsu, R.; Ali, A.; Alt, C.; Kudenko, Y.; Куденко, Юрий Григорьевич
We report the measurements of the single and double differential cross section of muon neutrino charged-current interactions on carbon with a single positively charged pion in the final state at the T2K off-axis near detector using 5.56 x 10(20) protons on target. The analysis uses data control samples for the background subtraction and the cross section signal, defined as a single negatively charged muon and a single positively charged pion exiting from the target nucleus, is extracted using an unfolding method. The model-dependent cross section, integrated over the T2K off-axis neutrino beam spectrum peaking at 0.6 GeV, is measured to be sigma = (11.76 +/- 0.44(stat) +/- 2.39(syst)) x 10(-40) cm(2) nucleon(-1). Various differential cross sections are measured, including the first measurement of the Adler angles for single charged pion production in neutrino interactions with heavy nuclei target.
Организационные подразделения
Организационная единица
Институт ядерной физики и технологий
Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.
Описание
T2K — это нейтринный эксперимент, предназначенный для изучения того, как нейтрино изменяются от одного аромата к другому во время путешествия ( нейтринные осцилляции ). Интенсивный пучок мюонных нейтрино генерируется на ядерно-физической площадке J-PARC на восточном побережье Японии и направляется через всю страну к детектору нейтрино Супер-Камиоканде в горах западной Японии. Луч измеряется один раз перед тем, как он покинет площадку J-PARC, с помощью ближнего детектора ND280 , и еще раз в Super-K: изменение измеренной интенсивности и состава луча используется для предоставления информации о свойствах нейтрино.