Publications
294 results found
Abe K, Adam J, Aihara H, et al., 2014, Observation of electron neutrino appearance in a muon neutrino beam, Physical Review Letters, Vol: 112, ISSN: 0031-9007
The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm232 and a CP violating phase δCP. In this neutrino oscillation scenario, assuming |Δm232|=2.4×10−3 eV2, sin2θ23=0.5, and Δm232>0 (Δm232<0), a best-fit value of sin22θ13=0.140+0.038−0.032 (0.170+0.045−0.037) is obtained at δCP=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ13 from reactor experiments, some values of δCP are disfavored at the 90% C.L
Abe K, Abgrall N, Aihara H, et al., 2014, Recent Results from the T2K Experiment, NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS, Vol: 246, Pages: 23-28, ISSN: 0920-5632
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- Citations: 2
Kurup A, Puri I, Uchida Y, et al., 2013, Optimisation of the beam line for COMET Phase-I, Pages: 2681-2683
The COMET experiment will search for very rare muon processes that will give us an insight into particle physics beyond the Standard Model. COMET requires an intense beam of muonswith amomentumless than 70MeV/c. This is achieved using an 8 GeV proton beam; a heavy metal target to primarily produce pions; a solenoid capture system; and a curved solenoid to perform charge and momentum selection. It was recently proposed to build COMET in two phases with physics measurements being made in both phases. This requires re-optimising the beam line for a shorter curved solenoid. This will affect the pion and muon yield; the momentum distributions at the detector; and the collimator scheme required. This paper will present the beam line design for COMET Phase-I, which aims to maximise the yield for low momentum muons suppressing sources of backgrounds in the beam. Copyright © 2013 by JACoW- cc Creative Commons Attribution 3.0 (CC-BY-3.0).
Kurup A, Puri I, Uchida Y, et al., 2013, Large emittance beam measurements for COMET Phase-I, Pages: 2684-2686
The COMET experiment will search for very rare muon processes that will give us an insight into particle physics beyond the Standard Model. COMET requires an intense beam of muonswith amomentumless than 70MeV/c. This is achieved using an 8 GeV proton beam; a heavy metal target to primarily produce pions; a solenoid capture system; and a curved solenoid to perform charge and momentum selection. Understanding the pion production yield and transport properties of the beam line is an important part of the experiment. The beam line is a continuous solenoid channel, so it is only possible to place a beam diagnostic device at the end of the beam line. Building COMET in two phases provides the opportunity to investigate the pion production yield and to measure the transport properties of the beam line in Phase-I. This paper will demonstrate how this will be done using the experimental set up for COMET Phase-I. Copyright © 2013 by JACoW- cc Creative Commons Attribution 3.0 (CC-BY-3.0).
Uchida Y, 2013, Measurement of neutrino oscillation parameters from muon neutrino disappearance with an off-axis beam, Physical Review Letters, Vol: 111, ISSN: 0031-9007
Allan D, Andreopoulos C, Angelsen C, et al., 2013, The electromagnetic calorimeter for the T2K near detector ND280, JOURNAL OF INSTRUMENTATION, Vol: 8, ISSN: 1748-0221
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- Citations: 49
Abe K, Abgrall N, Aihara H, et al., 2013, Evidence of electron neutrino appearance in a muon neutrino beam, PHYSICAL REVIEW D, Vol: 88, ISSN: 1550-7998
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- Citations: 133
Abe K, Abgrall N, Aihara H, et al., 2013, Measurement of the inclusive ν<sub>μ</sub> charged current cross section on carbon in the near detector of the T2K experiment, PHYSICAL REVIEW D, Vol: 87, ISSN: 1550-7998
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- Citations: 91
Abe K, Abgrall N, Aihara H, et al., 2013, T2K neutrino flux prediction (vol 87, 012001, 2013), PHYSICAL REVIEW D, Vol: 87, ISSN: 1550-7998
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- Citations: 2
Abe K, Abgrall N, Aihara H, et al., 2013, T2K neutrino flux prediction, PHYSICAL REVIEW D, Vol: 87, ISSN: 1550-7998
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- Citations: 161
Abe K, Abgrall N, Ajima Y, et al., 2012, Measurements of the T2K neutrino beam properties using the INGRID on-axis near detector, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 694, Pages: 211-223, ISSN: 0168-9002
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- Citations: 80
Pasternak J, Jenner LJ, Kurup A, et al., 2012, Status of the prism ffag design for the next generation muon-to-electron conversion experiment, Pages: 79-81
The PRISM Task Force continues to study high intensity and high quality muon beams needed for next generation lepton flavour violation experiments. In the PRISM case such beams have been proposed to be produced by sending a short proton pulse to a pion production target, capturing pions and performing RF phase rotation on the resulting muon beam in an FFAG ring. This paper summarizes the current status of the PRISM design obtained by the Task Force. In particular various designs for the PRISM FFAG ring are discussed and their performance compared to the baseline one, the injection/extraction systems and matching to the solenoid channels upstream and downstream of the FFAG ring are presented. The feasibility of the construction of the PRISM system is discussed. Copyright © 2012 by IEEE.
Cheng G, Huelsnitz W, Aguilar-Arevalo AA, et al., 2012, Dual baseline search for muon antineutrino disappearance at 0.1 eV<SUP>2</SUP> < Δ<i>m</i><SUP>2</SUP> < 100 eV<SUP>2</SUP>, PHYSICAL REVIEW D, Vol: 86, ISSN: 1550-7998
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- Citations: 90
Uchida Y, 2012, Experimental Proposal for Phase-I of the COMET Experiment at J-PARC
We hereby express our interest to employ a staged approach for the construction of the COherent Muon to Electron Transition (COMET) experiment that will search for neutrinoless μ−−e− conversions with a single-event sensitivity of 3×10−17. This sensitivity is a factor of 10,000 better than achieved by the SINDRUM-II experiment which set the current world’s best limit for μ−−e− conversions. The COMET experiment was given Stage-1 approval, of two stages, by the J-PARC Program Advisory Committee in 2009 and given the experiment number J-PARC E21.
Mahn KBM, Nakajima Y, Aguilar-Arevalo AA, et al., 2012, Dual baseline search for muon neutrino disappearance at 0.5 eV<SUP>2</SUP> < Δ<i>m</i><SUP>2</SUP> < 40 eV<SUP>2</SUP>, PHYSICAL REVIEW D, Vol: 85, ISSN: 1550-7998
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- Citations: 80
Uchida Y, Wascko MO, Wark D, et al., 2012, First muon-neutrino disappearance study with an off-axis beam, Physical Review d, Vol: 85
We report a measurement of muon-neutrino disappearance in the T2K experiment. The 295-km muon-neutrino beam from Tokai to Kamioka is the first implementation of the off-axis technique in a long-baseline neutrino oscillation experiment. With data corresponding to 1.43×1020 protons on target, we observe 31 fully-contained single μ-like ring events in Super-Kamiokande, compared with an expectation of 104±14 (syst) events without neutrino oscillations. The best-fit point for two-flavor νμ→ντ oscillations is sin2(2θ23)=0.98 and |Δm322|=2.65×10-3 eV2. The boundary of the 90% confidence region includes the points (sin2(2θ23),|Δm322|)=(1.0,3.1×10-3 eV2), (0.84, 2.65×10-3 eV2) and (1.0, 2.2×10-3 eV2).
Abe K, Abgrall N, Aihara H, et al., 2011, The T2K experiment, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, Vol: 659, Pages: 106-135, ISSN: 0168-9002
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- Citations: 492
Pasternak J, Jenner LJ, Kurup A, et al., 2011, Studies for the prism FFAG ring for the next generation muon to electron conversion experiment, Pages: 826-828
High intensity and high quality muon beams are needed for next generation lepton flavour violation experiments. Such beams can be produced by sending a short proton pulse to a pion production target, capturing the pions and performing RF phase rotation on the resulting muon beam in an FFAG ring. Such a solution was proposed for the PRISM project and this paper summarizes its current status. In particular the PRISM task force was created to address the accelerator and detector issues that need to be solved in order to realise the PRISM experiment. Alternative designs for the PRISM FFAG ring are discussed and their performance compared. The injection/extraction systems and matching to the solenoid channels upstream and downstream of the FFAG ring are presented. The future direction for the study will be outlined. Copyright © 2011 by IPAC'11/EPS-AG.
Cheng G, Mariani C, Alcaraz-Aunion JL, et al., 2011, Measurement of <i>K</i><SUP>+</SUP> production cross section by 8 GeV protons using high-energy neutrino interactions in the SciBooNE detector, PHYSICAL REVIEW D, Vol: 84, ISSN: 1550-7998
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- Citations: 19
Abe K, Abgrall N, Ajima Y, et al., 2011, Indication of electron neutrino appearance from an accelerator-produced off-axis muon neutrino beam., Phys Rev Lett, Vol: 107
The T2K experiment observes indications of ν(μ) → ν(e) appearance in data accumulated with 1.43×10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Δm(23)(2)| = 2.4×10(-3) eV(2), sin(2)2θ(23) = 1 and sin(2)2θ(13) = 0, the expected number of such events is 1.5±0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7×10(-3), equivalent to 2.5σ significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2θ(13) < 0.28(0.34) for δ(CP) = 0 and a normal (inverted) hierarchy.
Abe K, Abgrall N, Ajima Y, et al., 2011, Indication of Electron Neutrino Appearance from an Accelerator-Produced Off-Axis Muon Neutrino Beam, PHYSICAL REVIEW LETTERS, Vol: 107, ISSN: 0031-9007
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- Citations: 1095
Nakajima Y, Alcaraz-Aunion JL, Brice SJ, et al., 2011, Measurement of inclusive charged current interactions on carbon in a few-GeV neutrino beam, PHYSICAL REVIEW D, Vol: 83, ISSN: 1550-7998
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- Citations: 85
Pasternak J, Jenner LJ, Kurup A, et al., 2010, Accelerator and particle physics research for the next generation muon to electron conversion experiment - The PRISM task force, Pages: 3473-3475
The next generation of lepton flavour violation experiments will use high intensity and high quality muon beams. Such beams can be produced by sending a short proton pulse to the pion production target, capturing pions and performing RF phase rotation on the resulting muon beam in an FFAG ring, which was proposed for the PRISM project. A PRISM task force was created to address the accelerator and detector issues that need to be solved in order to realise the PRISM experiment. The parameters of the initial proton beam required and the PRISM experiment are reviewed. Alternative designs of the PRISM FFAG ring are presented and compared with the reference design. The ring injection/extraction system, matching with the solenoid channel and progress on the ring's main hardware systems like RF and kicker magnet are discussed. The progress and future directions of the study are presented in this paper.
Kurimoto Y, Alcaraz-Aunion JL, Brice SJ, et al., 2010, Improved measurement of neutral current coherent π<SUP>0</SUP> production on carbon in a few-GeV neutrino beam, PHYSICAL REVIEW D, Vol: 81, ISSN: 1550-7998
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- Citations: 43
Kurimoto Y, Alcaraz-Aunion JL, Brice SJ, et al., 2010, Measurement of inclusive neutral current π<SUP>0</SUP> production on carbon in a few-GeV neutrino beam, PHYSICAL REVIEW D, Vol: 81, ISSN: 1550-7998
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- Citations: 34
Bandyopadhyay A, Choubey S, Gandhi R, et al., 2009, Physics at a future Neutrino Factory and super-beam facility, REPORTS ON PROGRESS IN PHYSICS, Vol: 72, ISSN: 0034-4885
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- Citations: 175
Cui Y, Cui YG, Palmer R, et al., 2009, Conceptual Design Report for Experimental Search for Lepton Flavor Violating µ− − e− Conversion at Sensitivity of 10−16 with a Slow-Extracted Bunched Proton Beam (COMET)
Abe T, Aihara H, Oulos CA, et al., 2009, International Scoping Study (ISS) for a future neutrino factory and Super-Beam facility. Detectors and flux instrumentation for future neutrino facilities, JOURNAL OF INSTRUMENTATION, Vol: 4, ISSN: 1748-0221
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- Citations: 50
Hiraide K, Alcaraz-Aunion JL, Brice SJ, et al., 2008, Search for charged current coherent pion production on carbon in a few-GeV neutrino beam, PHYSICAL REVIEW D, Vol: 78, ISSN: 1550-7998
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- Citations: 103
Uchida Y, Ozaki H, Kichimi H, et al., 2008, Search for B̄0→Λc+Λ̄c- decay at Belle, Physical Review D - Particles, Fields, Gravitation and Cosmology, Vol: 77, ISSN: 1550-7998
We search for the doubly charmed baryonic decay B̄0→Λ c+Λ̄c-, in a data sample of 520×106 BB̄ events accumulated at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We find no significant signal and set an upper limit of B(B̄0→Λc+Λ̄c-)<6.2×10-5 at 90% confidence level. The result is significantly below a naive extrapolation from B(B-→Ξc0Λ̄c-) assuming a simple Cabibbo-suppression factor of |Vcd/Vcs|2. The small branching fraction may be attributed to a suppression due to the large momentum of the baryonic decay products, which has been observed in other charmed baryonic two-body B decays. © 2008 The American Physical Society.
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