-
K. Abe,
N. Abgrall,
H. Aihara,
T. Akiri,
J. B. Albert,
C. Andreopoulos,
S. Aoki,
A. Ariga,
T. Ariga,
S. Assylbekov, [......],
N. Yershov,
M. Yokoyama,
Ì T. Yuan,
A. Zalewska,
L. Zambelli,
K. Zaremba,
M. Ziembicki,
E. D. Zimmerman,
M. Zito,
and J. Zmuda
[show abstract]
[hide abstract]
ABSTRACT: T2K has performed the first measurement of \nu{\mu} inclusive charged current
interactions on carbon at neutrino energies of ~1 GeV where the measurement is
reported as a flux-averaged double differential cross section in muon momentum
and angle. The flux is predicted by the beam Monte Carlo and external data,
including the results from the NA61/SHINE experiment. The data used for this
measurement were taken in 2010 and 2011, with a total of 10.8 x 10^{19}
protons-on-target. The analysis is performed on 4485 inclusive charged current
interaction candidates selected in the most upstream fine-grained scintillator
detector of the near detector.
The flux-averaged total cross section is <\sigma_CC>_\phi =(6.91 +/- 0.13
(stat) +/- 0.84 (syst)) x10^{-39} cm^2/nucleon for a mean neutrino energy of
0.85 GeV.
02/2013;
-
Collaboration,
K. Abe,
N. Abgrall,
H. Aihara,
T. Akiri,
J. B. Albert,
C. Andreopoulos,
S. Aoki,
A. Ariga,
T. Ariga, [......],
N. Yershov,
M. Yokoyama,
T. Yuan,
A. Zalewska,
L. Zambelli,
K. Zaremba,
M. Ziembicki,
E. D. Zimmerman,
M. Zito,
J. Zmuda
[show abstract]
[hide abstract]
ABSTRACT: The Tokai-to-Kamioka (T2K) experiment studies neutrino oscillations using an
off-axis muon neutrino beam with a peak energy of about 0.6 GeV that originates
at the J-PARC accelerator facility. Interactions of the neutrinos are observed
at near detectors placed at 280 m from the production target and at the far
detector -- Super-Kamiokande (SK) -- located 295 km away. The flux prediction
is an essential part of the successful prediction of neutrino interaction rates
at the T2K detectors and is an important input to T2K neutrino oscillation and
cross section measurements. A FLUKA and GEANT3 based simulation models the
physical processes involved in the neutrino production, from the interaction of
primary beam protons in the T2K target, to the decay of hadrons and muons that
produce neutrinos. The simulation uses proton beam monitor measurements as
inputs. The modeling of hadronic interactions is re-weighted using thin target
hadron production data, including recent charged pion and kaon measurements
from the NA61/SHINE experiment. For the first T2K analyses the uncertainties on
the flux prediction are evaluated to be below 15% near the flux peak. The
uncertainty on the ratio of the flux predictions at the far and near detectors
is less than 2% near the flux peak.
11/2012;
-
N. Abgrall,
A. Aduszkiewicz,
T. Anticic,
N. Antoniou,
J. Argyriades,
B. Baatar,
A. Blondel,
J. Blumer,
M. Bogomilov,
A. Bravar, [......],
M. Hartz, A. K. Ichikawa,
H. Kubo,
A. D. Marino,
K. Matsuoka,
A. Murakami,
T. Nakaya,
K. Suzuki,
T. Yuan,
E. D. Zimmerman
[show abstract]
[hide abstract]
ABSTRACT: The T2K long-baseline neutrino oscillation experiment in Japan needs precise
predictions of the initial neutrino flux. The highest precision can be reached
based on detailed measurements of hadron emission from the same target as used
by T2K exposed to a proton beam of the same kinetic energy of 30 GeV. The
corresponding data were recorded in 2007-2010 by the NA61/SHINE experiment at
the CERN SPS using a replica of the T2K graphite target. In this paper details
of the experiment, data taking, data analysis method and results from the 2007
pilot run are presented. Furthermore, the application of the NA61/SHINE
measurements to the predictions of the T2K initial neutrino flux is described
and discussed.
07/2012;
-
Collaboration,
K. Abe,
N. Abgrall,
Y. Ajima,
H. Aihara,
J. B. Albert,
C. Andreopoulos,
B. Andrieu,
M. D. Anerella,
S. Aoki, [......],
M. Yokoyama,
T. Yuan,
A. Zalewska,
J. Zalipska,
L. Zambelli,
K. Zaremba,
M. Ziembicki,
E. D. Zimmerman,
M. Zito,
J. Zmuda
[show abstract]
[hide abstract]
ABSTRACT: 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 10**20 protons on target, we observe 31
fully-contained single muon-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 nu_mu -> nu_tau oscillations is sin**2(2
theta_23) = 0.98 and |\Delta m**2_32| = 2.65 10**-3 eV**2. The boundary of the
90 % confidence region includes the points (sin**2(2 theta_23),|\Delta
m**2_32|) = (1.0, 3.1 10**-3 eV**2), (0.84, 2.65 10**-3 eV**2) and (1.0, 2.2
10**-3 eV**2).
01/2012;
-
K Abe,
N. Abgrall,
Y. Ajima,
H. Aihara,
J. B. Albert,
C. Andreopoulos,
B Andrieu,
M. D. Anerella,
S Aoki,
O. Araoka, [......],
M Yokoyama,
T Yuan,
A Zalewska,
J. Zalipska,
L. Zambelli,
K Zaremba,
M Ziembicki,
E. D. Zimmerman,
M Zito,
J. Zmuda
[show abstract]
[hide abstract]
ABSTRACT: Precise measurement of neutrino beam direction and intensity was achieved
based on a new concept with modularized neutrino detectors. INGRID (Interactive
Neutrino GRID) is an on-axis near detector for the T2K long baseline neutrino
oscillation experiment. INGRID consists of 16 identical modules arranged in
horizontal and vertical arrays around the beam center. The module has a
sandwich structure of iron target plates and scintillator trackers. INGRID
directly monitors the muon neutrino beam profile center and intensity using the
number of observed neutrino events in each module. The neutrino beam direction
is measured with accuracy better than 0.4 mrad from the measured profile
center. The normalized event rate is measured with 4% precision.
11/2011;
-
[show abstract]
[hide abstract]
ABSTRACT: Semiconductor detectors made of CdTe crystal have high gamma-ray detection
efficiency and are usable at room temperature. However, the energy resolution
of CdTe detectors for MeV gamma-rays is rather poor because of the significant
hole trapping effect. We have developed a method to improve the energy
resolution by correcting the pulse height using the waveform of the signal and
achieved 2.0% (FWHM) energy resolution for 662keV gamma-rays. Best energy
resolution was achieved at temperatures between -10 degrees C and 0 degrees C.
11/2011;
-
Super-Kamiokande Collaboration: K. Abe,
Y. Hayato,
T Iida,
K Ishihara,
J. Kameda,
Y. Koshio,
A. Minamino,
C. Mitsuda,
M Miura,
S Moriyama, [......],
Y Totsuka,
S Chen,
Z Deng,
Y Liu,
D. Kielczewska,
H. G. Berns,
K. K. Shiraishi,
E. Thrane,
K. Washburn,
R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: A search for neutron-antineutron (n - nbar) oscillation, a process with
|\DeltaB| = 2 that has been predicted by right-left (R-L) symmetric gauge
theories, was undertaken using the 24.5\times10^33 neutron-yrs exposure of
Super- Kamiokande I, in an analysis that included the significant sources of
experimental uncertainties. No evidence for n - nbar oscillation was found, the
lower limit of the lifetime for neutrons bound in ^16 O was determined to be
1.89 \times 10^32 yrs at the 90% confidence level (C.L.), and the corresponding
limit for the oscillation time for free neutrons was calculated to be 2.44
\times 10^8 sec using a theoretical suppression factor of 1.0 \times 10^23
sec^-1.
09/2011;
-
K Abe,
T Abe,
H. Aihara,
Y Fukuda,
Y. Hayato,
K Huang, A. K. Ichikawa,
M Ikeda,
K Inoue,
H. Ishino, [......],
A. T. Suzuki,
Y Suzuki,
A Takeda,
Y Takeuchi,
H. K. M. Tanaka,
S. Tasaka,
T Tomura,
M. R. Vagins,
J Wang,
M Yokoyama
[show abstract]
[hide abstract]
ABSTRACT: We propose the Hyper-Kamiokande (Hyper-K) detector as a next generation
underground water Cherenkov detector. It will serve as a far detector of a long
baseline neutrino oscillation experiment envisioned for the upgraded J-PARC,
and as a detector capable of observing -- far beyond the sensitivity of the
Super-Kamiokande (Super-K) detector -- proton decays, atmospheric neutrinos,
and neutrinos from astronomical origins. The baseline design of Hyper-K is
based on the highly successful Super-K, taking full advantage of a well-proven
technology. (to be continued)
09/2011;
-
K Abe,
N Abgrall,
Y Ajima,
H Aihara,
J B Albert,
C Andreopoulos,
B Andrieu,
S Aoki,
O Araoka,
J Argyriades, [......],
N Yershov,
M Yokoyama,
A Zalewska,
J Zalipska,
L Zambelli,
K Zaremba,
M Ziembicki,
E D Zimmerman,
M Zito,
J Żmuda
[show abstract]
[hide abstract]
ABSTRACT: 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.
Physical Review Letters 07/2011; 107(4):041801. · 7.37 Impact Factor
-
Collaboration,
N. Abgrall,
H. Aihara,
Y. Ajima,
J. B. Albert,
D. Allan,
P. -A. Amaudruz,
C. Andreopoulos,
B. Andrieu,
M. D. Anerella, [......],
S. Yen,
N. Yershov,
M. Yokoyama,
A. Zalewska,
J. Zalipska,
K. Zaremba,
M. Ziembicki,
E. D. Zimmerman,
M. Zito,
J. Zmuda
[show abstract]
[hide abstract]
ABSTRACT: The T2K experiment is a long-baseline neutrino oscillation experiment. Its
main goal is to measure the last unknown lepton sector mixing angle
{\theta}_{13} by observing {\nu}_e appearance in a {\nu}_{\mu} beam. It also
aims to make a precision measurement of the known oscillation parameters,
{\Delta}m^{2}_{23} and sin^{2} 2{\theta}_{23}, via {\nu}_{\mu} 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.
06/2011;
-
K. Matsuoka, A.K. Ichikawa,
H. Kubo,
K. Maeda,
T. Maruyama,
C. Matsumura,
A. Murakami,
T. Nakaya,
K. Nishikawa,
T. Ozaki,
K. Sakashita,
K. Suzuki,
S.Y. Suzuki,
K. Tashiro,
K. Yamamoto,
M. Yokoyama
[show abstract]
[hide abstract]
ABSTRACT: This article describes the design and performance of the muon monitor for the T2K (Tokai-to-Kamioka) long baseline neutrino oscillation experiment. The muon monitor consists of two types of detector arrays: ionization chambers and silicon PIN photodiodes. It measures the intensity and profile of muons produced, along with neutrinos, in the decay of pions. The measurement is sensitive to the intensity and direction of the neutrino beam. The linearity and stability of the detectors were measured in beam tests to be within 2.4% and 1.5%, respectively. Based on the test results, the precision of the beam direction measured by the muon monitor is expected to be 0.25 mrad.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 08/2010;
-
E. Thrane,
K. Abe,
Y. Hayato,
T. Iida,
M. Ikeda,
J. Kameda,
K. Kobayashi,
Y. Koshio,
M. Miura,
S. Moriyama, [......],
G. Gong,
Y. Heng,
T. Xue,
Z. Yang,
H. Zhang,
D. Kielczewska,
P. Mijakowski,
K. Connolly,
M. Dziomba,
R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: It has been hypothesized that large fluxes of neutrinos may be created in astrophysical "cosmic accelerators." The primary background for a search for astrophysical neutrinos comes from atmospheric neutrinos, which do not exhibit the pointlike directional clustering that characterizes a distant astrophysical signal. We perform a search for neutrino point sources using the upward-going muon data from three phases of operation (SK-I, SK-II, and SK-III) spanning 2623 days of live time taken from 1996 April 1 to 2007 August 11. The search looks for signals from suspected galactic and extragalactic sources, transient sources, and uncataloged sources. While we find interesting signatures from two objects—RX J1713.7–3946 (97.5% CL) and GRB 991004D (95.3% CL)—these signatures lack compelling statistical significance given trial factors. We set limits on the flux and fluence of neutrino point sources above energies of 1.6 GeV.
The Astrophysical Journal 09/2009; 704(1):503. · 6.02 Impact Factor
-
E. Thrane,
K. Abe,
Y. Hayato,
T. Iida,
M. Ikeda,
J. Kameda,
K. Kobayashi,
Y. Koshio,
M. Miura,
S. Moriyama, [......],
Y. Heng,
T. Xue,
Z. Yang,
H. Zhang,
D. Kielczewska,
P. Mijakowski,
H. G. Berns,
K. Connolly,
M. Dziomba,
and R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: We perform a search for neutrinos coincident with GRB 080319B—the brightest GRB observed to date—in a ±1000 s window. No statistically significant coincidences were observed and we thereby obtain an upper limit on the fluence of neutrino-induced muons from this source. From this we apply reasonable assumptions to derive a limit on neutrino fluence from the GRB.
The Astrophysical Journal 05/2009; 697(1):730. · 6.02 Impact Factor
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M. Ikeda,
A. Takeda,
Y. Fukuda,
M. R. Vagins,
K. Abe,
T. Iida,
K. Ishihara,
J. Kameda,
Y. Koshio,
A. Minamino, [......],
Y. Liu,
D. Kielczewska,
J. Zalipska,
H. Berns,
R. Gran,
K. K. Shiraishi,
A. Stachyra,
E. Thrane,
K. Washburn,
R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: We report the results of a search for neutrino bursts from supernova explosions using the Super-Kamiokande detector. Super-Kamiokande is sensitive to core-collapse supernova explosions via observation of their neutrino emissions. The expected number of events comprising such a burst is ~104, and the average energy of the neutrinos is in the range of a few tens of MeV for a core-collapse supernova explosion at a typical distance in our galaxy (10 kpc); this strong signal means that the detection efficiency anywhere within our galaxy and well past the Magellanic Clouds should be 100%. We examined a data set taken from 1996 May to 2001 July, and from 2002 December to 2005 October, corresponding to 2589.2 live days. However, there is no evidence of such a supernova explosion during the data-taking period. The 90% C.L. upper limit on the rate of core-collapse supernova explosions out to distances of 100 kpc is found to be 0.32 SN yr-1.
The Astrophysical Journal 12/2008; 669(1):519. · 6.02 Impact Factor
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K. Abe,
J. Hosaka,
T. Iida,
K. Ishihara,
J. Kameda,
Y. Koshio,
A. Minamino,
C. Mitsuda,
M. Miura,
S. Moriyama, [......],
M. Koshiba,
D. Kielczewska,
J. Zalipska,
H. Berns,
R. Gran,
K. K. Shiraishi,
A. Stachyra,
E. Thrane,
K. Washburn,
R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: We present the results from several studies used to search for astrophysical sources of high-energy neutrinos using the Super-Kamiokande I (1996 April-2001 July) neutrino-induced upward-going muon data. The data set consists of 2359 events with minimum energy 1.6 GeV, of which 1892 are through-going and 467 stop within the detector. The results of several independent analyses are presented, including searches for point sources using directional and temporal information and a search for signatures of cosmic-ray interactions with the interstellar medium in the upward-going muons. No statistically significant evidence for point sources or any diffuse flux from the plane of the Galaxy was found, so specific limits on fluxes from likely point sources are calculated. The 90% confidence level (CL) upper limits on upward-going muon flux from astronomical sources that are located in the southern hemisphere and always under the horizon for Super-Kamiokande are ~ × 10-15 cm-2 s-1.
The Astrophysical Journal 12/2008; 652(1):198. · 6.02 Impact Factor
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S. Mine,
J. L. Alcaraz,
S. Andringa,
S. Aoki,
J. Argyriades,
K. Asakura,
R. Ashie,
F. Berghaus,
H. Berns,
H. Bhang, [......],
S. Yamada,
Y. Yamada,
S. Yamamoto,
C. Yanagisawa,
N. Yershov,
H. Yokoyama,
M. Yokoyama,
J. Yoo,
M. Yoshida,
J. Zalipska
[show abstract]
[hide abstract]
ABSTRACT: The atmospheric neutrino background for proton decay via p→e+π0 in ring imaging water Cherenkov detectors is studied with an artificial accelerator neutrino beam for the first time. In total, 3.14×105 neutrino events corresponding to about 10 megaton-years of atmospheric neutrino interactions were collected by a 1000 ton water Cherenkov detector (KT). The KT charged-current single π0 production data are well reproduced by simulation programs of neutrino and secondary hadronic interactions used in the Super-Kamiokande (SK) proton decay search. The obtained p→e+π0 background rate by the KT data for SK from the atmospheric neutrinos whose energies are below 3 GeV is 1.63-0.33+0.42(stat)-0.51+0.45(syst)(megaton-year)-1. This result is also relevant to possible future, megaton-scale water Cherenkov detectors.
Phys. Rev. D. 02/2008; 77(3).
-
K Abe,
Y Hayato,
T Iida,
K Ishihara,
J Kameda,
Y Koshio,
A Minamino,
C Mitsuda,
M Miura,
S Moriyama, [......],
K Nishijima,
H Ishino,
Y Watanabe,
M Koshiba,
D Kielczewska,
J Zalipska,
H G Berns,
K K Shiraishi,
K Washburn,
R J Wilkes
[show abstract]
[hide abstract]
ABSTRACT: A search for the appearance of tau neutrinos from nu(mu) <--> nu(tau) oscillations in the atmospheric neutrinos has been performed using 1489.2 days of atmospheric neutrino data from the Super-Kamiokande-I experiment. A best fit tau neutrino appearance signal of 138+/-48(stat)-32(+15)(syst) events is obtained with an expectation of 78+/-26(syst). The hypothesis of no tau neutrino appearance is disfavored by 2.4 sigma.
Physical Review Letters 10/2006; 97(17):171801. · 7.37 Impact Factor
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S Yamamoto,
J Zalipska,
E Aliu,
S Andringa,
S Aoki,
J Argyriades,
K Asakura,
R Ashie,
F Berghaus,
H Berns, [......],
C W Walter,
W Wang,
R J Wilkes,
S Yamada,
C Yanagisawa,
N Yershov,
H Yokoyama,
M Yokoyama,
J Yoo,
M Yoshida
[show abstract]
[hide abstract]
ABSTRACT: We performed an improved search for nu(mu) --> nu(e) oscillation with the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment, using the full data sample of 9.2 x 10(19) protons on target. No evidence for a nu(e) appearance signal was found, and we set bounds on the nu(mu) --> nu(e) oscillation parameters. At Deltam(2)=2.8 x 10(-3) eV(2), the best-fit value of the K2Knu(mu) disappearance analysis, we set an upper limit of sin(2)2theta(mue) < 0.13 at a 90% confidence level.
Physical Review Letters 06/2006; 96(18):181801. · 7.37 Impact Factor
-
M Hasegawa,
E Aliu,
S Andringa,
S Aoki,
J Argyriades,
K Asakura,
R Ashie,
H Berns,
H Bhang,
A Blondel, [......],
R J Wilkes,
S Yamada,
S Yamamoto,
C Yanagisawa,
N Yershov,
H Yokoyama,
M Yokoyama,
J Yoo,
M Yoshida,
J Zalipska
[show abstract]
[hide abstract]
ABSTRACT: We report the result from a search for charged-current coherent pion production induced by muon neutrinos with a mean energy of 1.3 GeV. The data are collected with a fully active scintillator detector in the K2K long-baseline neutrino oscillation experiment. No evidence for coherent pion production is observed, and an upper limit of is set on the cross section ratio of coherent pion production to the total charged-current interaction at 90% confidence level. This is the first experimental limit for coherent charged pion production in the energy region of a few GeV.
Physical Review Letters 01/2006; 95(25):252301. · 7.37 Impact Factor
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S. Yamamoto,
S. Andringa,
S. Aoki,
S. Choi,
U. Dore,
X. Espinal,
J.J. Gomez-Cadenas,
R. Gran,
M. Hasegawa,
K. Hayashi, [......],
T. Takahashi,
Y. Takubo,
M. Tanaka,
R. Terri,
A. Tornero-Lopez,
S. Ueda,
L. Whitehead,
R.J. Wilkes,
M. Yokoyama,
M. Yoshida
[show abstract]
[hide abstract]
ABSTRACT: A new near detector for the K2K long baseline neutrino experiment, the SciBar, was constructed and started data taking to study neutrino interactions. In K2K, neutrino oscillation is studied by comparing the number of neutrino interactions and energy spectrum between near and far detectors. In order to study neutrino oscillations more precisely, it is necessary to improve the measurement of neutrino spectrum and interactions below 1 GeV, where the latest K2K results suggest maximum oscillation. For that purpose, SciBar is designed to be fully active with fine segmentation. We present the design and basic performance. All detector components have been working as expected. Also presented are the measurements of charged current interactions which are used in the latest K2K oscillation analysis
IEEE Transactions on Nuclear Science 01/2006; · 1.45 Impact Factor
