-
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;
-
C. Regis,
K. Abe,
Y. Hayato,
K. Iyogi,
J. Kameda,
Y. Koshio,
Ll. Marti, M. Miura,
S. Moriyama,
M. Nakahata, [......],
M. Yokoyama,
K. Martens,
M. R. Vagins,
S. Chen,
H. Sui,
Z. Yang,
H. Zhang,
K. Connolly,
M. Dziomba,
R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: We have searched for proton decay via p→μ+K0 using data from a 91.7 kiloton·year exposure of Super-Kamiokande- I, a 49.2 kiloton·year exposure of Super-Kamiokande II, and a 31.9 kiloton·year exposure of Super-Kamiokande III. The number of candidate events in the data was consistent with the atmospheric neutrino background expectation and no evidence for proton decay in this mode was found. We set a partial lifetime lower limit of 1.6×1033 years at the 90% confidence level.
Phys. Rev. D. 07/2012; 86(1).
-
H. Nishino,
K. Abe,
Y. Hayato,
T. Iida,
M. Ikeda,
J. Kameda,
Y. Koshio, M. Miura,
S. Moriyama,
M. Nakahata, [......],
M. R. Vagins,
S. Chen,
Y. Heng,
J. Liu,
Z. Yang,
H. Zhang,
D. Kielczewska,
K. Connolly,
E. Thrane,
R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: Searches for a nucleon decay into a charged antilepton (e+ or μ+) plus a light meson (π0, π-, η, ρ0, ρ-, ω) were performed using the Super-Kamiokande I and II data. Twelve nucleon decay modes were searched for. The total exposure is 140.9 kiloton·years, which includes a 91.7 kiloton·year exposure (1489.2 live days) of Super-Kamiokande-I and a 49.2 kiloton·year exposure (798.6 live days) of Super-Kamiokande II. The number of candidate events in the data was consistent with the atmospheric neutrino background expectation. No significant evidence for a nucleon decay was observed in the data. Thus, lower limits on the nucleon partial lifetime at 90% confidence level were obtained. The limits range from 3.6×1031 to 8.2×1033 years, depending on the decay modes.
Phys. Rev. D. 06/2012; 85(11).
-
The Super-Kamiokande Collaboration: C. Regis,
K. Abe,
Y. Hayato,
K. Iyogi,
J. Kameda,
Y. Koshio,
Ll. Marti, M. Miura,
S. Moriyama,
M. Nakahata, [......],
M. Yokoyama,
K. Martens,
M. R. Vagins,
S. Chen,
H. Sui,
Z. Yang,
H. Zhang,
K. Connolly,
M. Dziomba,
R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: We have searched for proton into muon plus neutral kaon using data from a
91.7 kiloton-year exposure of Super-Kamiokande-I, a 49.2 kiloton-year exposure
of Super-Kamiokande-II, and a 31.9 kiloton-year exposure of
Super-Kamiokande-III. The number of candidate events in the data was consistent
with the atmospheric neutrino background expectation and no evidence for proton
decay in this mode was found. We set a partial lifetime lower limit of
1.6x10^33 years at the 90% confidence level.
05/2012;
-
[show abstract]
[hide abstract]
ABSTRACT: High-damping materials are widely used in engineering fields. In order to increase the precision of vibration control to different
levels, high-damping materials with high-rigidity are required. This study attempts to develop a new high-damping high-rigidity
material using ductile ceramics based on the Al2TiO5–MgTi2O5 system, which has many continuous microcracks along the grain boundaries. Ductile ceramics have high internal friction (Q
−1=0.01–0.037), but very low rigidity (<10GPa). The rigidity of Al2TiO5–MgTi2O5 ceramics was improved by combining them with a polymer such as acrylic resin. The Young’s modulus and internal friction of
the composites of Al2TiO5–MgTi2O5 ceramics and acrylic resin are investigated. They show high-damping capacity (Q
−1=0.03–0.04) with high rigidity (E=50–60GPa), and their properties depend on those of the polymer. Thus, the composites fabricated using the above method
can serve as high-damping high-rigidity materials.
Journal of Materials Science 04/2012; 44(1):93-101. · 2.02 Impact Factor
-
Super-Kamiokande Collaboration: H. Nishino,
K. Abe,
Y. Hayato,
T. Iida,
M. Ikeda,
J. Kameda,
Y. Koshio, M. Miura,
S. Moriyama,
M. Nakahata, [......],
M. R. Vagins,
S. Chen,
Y. Heng,
J. Liu,
Z. Yang,
H. Zhang,
D. Kielczewska,
K. Connolly,
E. Thrane,
R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: Searches for a nucleon decay into a charged anti-lepton (e^+ or {\mu}^+) plus
a light meson ({\pi}^0, {\pi}^-, {\eta}, {\rho}^0, {\rho}^-, {\omega}) were
performed using the Super-Kamiokande I and II data. Twelve nucleon decay modes
were searched for. The total exposure is 140.9 kiloton \cdot years, which
includes a 91.7 kiloton \cdot year exposure (1489.2 live days) of
Super-Kamiokande-I and a 49.2 kiloton \cdot year exposure (798.6 live days) of
Super-Kamiokande-II. The number of candidate events in the data was consistent
with the atmospheric neutrino background expectation. No significant evidence
for a nucleon decay was observed in the data. Thus, lower limits on the nucleon
partial lifetime at 90% confidence level were obtained. The limits range from
3.6 \times 10^31 to 8.2 \times 10^33 years, depending on the decay modes.
03/2012;
-
The Super-Kamiokande Collaboration: K. Ueno,
K. Abe,
Y. Hayato,
T. Iida,
K. Iyogi,
J. Kameda,
Y. Koshio,
Y. Kozuma, M. Miura,
S. Moriyama, [......],
S. Chen,
Y. Heng,
Z. Yang,
H. Zhang,
D. Kielczewska,
P. Mijakowski,
K. Connolly,
M. Dziomba,
E. Thrane,
R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: GUT monopoles captured by the Sun's gravitation are expected to catalyze
proton decays via the Callan-Rubakov process. In this scenario, protons, which
initially decay into pions, will ultimately produce \nu_{e}, \nu_{\mu} and
\bar{\nu}_{\mu}. After undergoing neutrino oscillation, all neutrino species
appear when they arrive at the Earth, and can be detected by a 50,000 metric
ton water Cherenkov detector, Super-Kamiokande (SK). A search for low energy
neutrinos in the electron total energy range from 19 to 55 MeV was carried out
with SK and gives a monopole flux limit of F_M(\sigma_0/1 mb) < 6.3 \times
10^{-24} (\beta_M/10^{-3})^2 cm^{-2} s^{-1} sr^{-1} at 90% C.L., where \beta_M
is the monopole velocity in units of the speed of light and \sigma_0 is the
catalysis cross section at \beta_M=1. The obtained limit is more than eight
orders of magnitude more stringent than the current best cosmic-ray
supermassive monopole flux limit, F_M < 1 \times 10^{-15} cm^{-2} s^{-1}
sr^{-1} for \beta_M < 10^{-3} and also two orders of magnitude lower than the
result of the Kamiokande experiment, which used a similar detection method.
03/2012;
-
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,
Y Hayato,
T Iida,
M Ikeda,
K Iyogi,
J Kameda,
Y Koshio,
Y Kozuma, M Miura,
S Moriyama, [......],
Y Totsuka,
S Chen,
Y Heng,
Z Yang,
H Zhang,
D Kielczewska,
P Mijakowski,
K Connolly,
M Dziomba,
R J Wilkes
[show abstract]
[hide abstract]
ABSTRACT: We present a search for differences in the oscillations of antineutrinos and neutrinos in the Super-Kamiokande-I, -II, and -III atmospheric neutrino sample. Under a two-flavor disappearance model with separate mixing parameters between neutrinos and antineutrinos, we find no evidence for a difference in oscillation parameters. Best-fit antineutrino mixing is found to be at (Δm2,sin2 2θ)=(2.0×10(-3) eV2, 1.0) and is consistent with the overall Super-K measurement.
Physical Review Letters 12/2011; 107(24):241801. · 7.37 Impact Factor
-
The Super-Kamiokande Collaboration: K. Bays,
T. Iida,
K. Abe,
Y. Hayato,
K. Iyogi,
J. Kameda,
Y. Koshio,
L. Marti, M. Miura,
S. Moriyama, [......],
Y. Totsuka,
M. Yokoyama,
Y. Heng,
S. Chen,
H. Zhang,
Z. Yang,
P. Mijakowski,
K. Connolly,
M. Dziomba,
R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: A new Super-Kamiokande (SK) search for Supernova Relic Neutrinos (SRNs) was
conducted using 2853 live days of data. Sensitivity is now greatly improved
compared to the 2003 SK result, which placed a flux limit near many theoretical
predictions. This more detailed analysis includes a variety of improvements
such as increased efficiency, a lower energy threshold, and an expanded data
set. New combined upper limits on SRN flux are between 2.8 and 3.0 nu_e cm^-2
s^-1 > 16 MeV total positron energy (17.3 MeV E_nu).
11/2011;
-
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;
-
T. Tanaka,
K. Abe,
Y. Hayato,
T. Iida,
J. Kameda,
Y. Koshio,
Y. Kouzuma, M. Miura,
S. Moriyama,
M. Nakahata, [......],
Y. Heng,
Z. Yang,
H. Zhang,
D. Kielczewska,
P. Mijakowski,
K. Connolly,
M. Dziomba,
E. Thrane,
R. J. Wilkes,
and (The Super-Kamiokande Collaboration
[show abstract]
[hide abstract]
ABSTRACT: We present the result of an indirect search for high energy neutrinos from Weakly Interacting Massive Particle (WIMP) annihilation in the Sun using upward-going muon (upmu) events at Super-Kamiokande. Data sets from SKI-SKIII (3109.6 days) were used for the analysis. We looked for an excess of neutrino signal from the Sun as compared with the expected atmospheric neutrino background in three upmu categories: stopping, non-showering, and showering. No significant excess was observed. The 90% C.L. upper limits of upmu flux induced by WIMPs of 100 GeV c-2 were 6.4 × 10–15 cm–2 s–1 and 4.0 × 10–15 cm–2 s–1 for the soft and hard annihilation channels, respectively. These limits correspond to upper limits of 4.5 × 10–39 cm–2 and 2.7 × 10–40 cm–2 for spin-dependent WIMP-nucleon scattering cross sections in the soft and hard annihilation channels, respectively.
The Astrophysical Journal 11/2011; 742(2):78. · 6.02 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We study the vortex dynamics of NaxCa1−xFe2As2 single crystals with x = 0.5 (underdoped) and x = 0.75 (optimally doped), having Tc ≈ 19.4 and 33.4 K, respectively, by performing magnetization measurements of the critical current density Jc and flux creep rate S. We find that the Jc versus temperature, T, dependence is consistent with δTc pinning, indicating strong pinning associated with randomly distributed defects larger than the coherence length ξ. The temperature dependence of S shows a crossover between glassy (elastic) and plastic creep regimes. The boundary Tcr(H) between both creep regimes coincides with the upper limit of the regime of strong pinning by nanoparticles. The glassy exponent μ in the optimally doped crystal is consistent with the thermal collective creep theory previously applied to cuprate superconductors, but in the underdoped sample the plateau in S(T) indicates that μ ≈ 3–3.3, a value larger than the existing theoretical predictions. We discuss the quantum creep contributions in both samples.
Phys. Rev. B. 09/2011; 84(9).
-
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;
-
G. Mitsuka,
K Abe,
Y. Hayato,
T Iida,
M Ikeda,
J. Kameda,
Y. Koshio, M Miura,
S Moriyama,
M Nakahata, [......],
Y Totsuka,
S Chen,
J Liu,
Y. Heng,
Z Yang,
H Zhang,
D. Kielczewska,
K Connolly,
E. Thrane,
R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: In this paper we study non-standard neutrino interactions as an example of
physics beyond the standard model using atmospheric neutrino data collected
during the Super-Kamiokande I(1996-2001) and II(2003-2005) periods. We focus on
flavor-changing-neutral-currents (FCNC), which allow neutrino flavor
transitions via neutral current interactions, and effects which violate lepton
non-universality (NU) and give rise to different neutral-current
interaction-amplitudes for different neutrino flavors. We obtain a limit on the
FCNC coupling parameter, varepsilon_{mu tau}, |varepsilon_{mu tau}|<1.1 x
10^{-2} at 90%C.L. and various constraints on other FCNC parameters as a
function of the NU coupling, varepsilon_{e e}. We find no evidence of
non-standard neutrino interactions in the Super-Kamiokande atmospheric data.
09/2011;
-
The Super-Kamiokande Collaboration: T. Tanaka,
K. Abe,
Y. Hayato,
T. Iida,
J. Kameda,
Y. Koshio,
Y. Kouzuma, M. Miura,
S. Moriyama,
M. Nakahata, [......],
S. Chen,
Y. Heng,
Z. Yang,
H. Zhang,
D. Kielczewska,
P. Mijakowski,
K. Connolly,
M. Dziomba,
E. Thrane,
R. J. Wilkes
[show abstract]
[hide abstract]
ABSTRACT: We present the result of an indirect search for high energy neutrinos from
WIMP annihilation in the Sun using upward-going muon (upmu) events at
Super-Kamiokande. Datasets from SKI-SKIII (3109.6 days) were used for the
analysis. We looked for an excess of neutrino signal from the Sun as compared
with the expected atmospheric neutrino background in three upmu categories:
stopping, non-showering, and showering. No significant excess was observed. The
90% C.L. upper limits of upward-going muon flux induced by WIMPs of 100
GeV/c$^2$ were 6.4$\times10^{-15}$ cm$^{-2}$ sec$^{-1}$ and 4.0$\times10^{-15}$
cm$^{-2}$ sec$^{-1}$ for the soft and hard annihilation channels, respectively.
These limits correspond to upper limits of 4.5$\times10^{-39}$ cm$^{-2}$ and
2.7$\times10^{-40}$ cm$^{-2}$ for spin-dependent WIMP-nucleon scattering cross
sections in the soft and hard annihilation channels, respectively.
08/2011;
-
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
-
[show abstract]
[hide abstract]
ABSTRACT: The improvement of critical current density properties of REBCO coated conductors for applications in superconducting power devices is desired. It is known that the critical current density J<sub>c</sub> of REBCO thin films made by the TFA-MOD method in a magnetic field is greatly improved by the introduction of BZO-nanoparticles of a non-superconducting phase as artificial pinning centers. In addition, the field angle anisotropy can also be reduced by isotropic flux pinning interactions of nanoparticles. However, a detailed report on the mechanism of flux pinning with a quantitative investigation in such coated conductors has not been given. In this study, the field angle dependence of the critical current density is measured for TFA-MOD-processed YGdBCO coated conductor with a superconducting layer of 0.65 μm thick, and the results are theoretically analysed to clarify the flux pinning mechanism.
IEEE Transactions on Appiled Superconductivity 07/2011; · 1.04 Impact Factor
