8,991 research outputs found
Measurements of neutrino oscillation in appearance and disappearance channels by the T2K experiment with 6.6 x 10(20) protons on target
111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee comments111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee comments111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee commentsWe thank the J-PARC staff for superb accelerator performance and the CERN NA61/SHINE Collaboration for providing valuable particle production data. We acknowledge the support of MEXT, Japan; NSERC, NRC, and CFI, Canada; CEA and CNRS/IN2P3, France; DFG, Germany; INFN, Italy; National Science Centre (NCN), Poland; RSF, RFBR and MES, Russia; MINECO and ERDF funds, Spain; SNSF and SER, Switzerland; STFC, UK; and the U. S. Deparment of Energy, USA. We also thank CERN for the UA1/NOMAD magnet, DESY for the HERA-B magnet mover system, NII for SINET4, the WestGrid and SciNet consortia in Compute Canada, GridPP, UK, and the Emerald High Performance Computing facility in the Centre for Innovation, UK. In addition, participation of individual researchers and institutions has been further supported by funds from ERC (FP7), EU; JSPS, Japan; Royal Society, UK; and DOE Early Career program, USA
Estimation of the mean of a discrete parameter, covariance stationary, stochastic process in rotation sampling
Constrained optimization procedure for deriving linear estimator of population mean in rotation samplin
Long baseline accelerator neutrino experiments
Neutrino oscillation has been observed and shown to be consistent with the idea that the oscillations are due to the co-existence of three mass and three flavor eigen-states. This is confirmed by the dependence on L/E and the
observation of the explicit flavor changes associated with the oscillations in νμ → ντ and νμ → νe. The three mixing angles, which corresponds to the mixing of the three
neutrino states, have been measured. They are large compared to those of quarks, especially the mixing of second and third generation is almost maximal. Reactor and accelerator data are consistent with three-neutrino framework at 10% level. Next generation long baseline neutrino experiments will clarify the mass hierarchy,
relation of νμ, ντ and second, third mass states and may discover CP violation in neutrino oscillation. However, to investigate the structure of flavor physics further, it will be necessary to have critical tests of the three-neutrino framework itself and the origin of possible CP violation in lepton
Weibel instability and associated strong fields in a fully 3D simulation of a relativistic shock
Plasma instabilities (e.g., Buneman, Weibel and other two-stream
instabilities) excited in collisionless shocks are responsible for particle
(electron, positron, and ion) acceleration. Using a new 3-D relativistic
particle-in-cell code, we have investigated the particle acceleration and shock
structure associated with an unmagnetized relativistic electron-positron jet
propagating into an unmagnetized electron-positron plasma. The simulation has
been performed using a long simulation system in order to study the nonlinear
stages of the Weibel instability, the particle acceleration mechanism, and the
shock structure. Cold jet electrons are thermalized and slowed while the
ambient electrons are swept up to create a partially developed hydrodynamic
(HD) like shock structure. In the leading shock, electron density increases by
a factor of 3.5 in the simulation frame. Strong electromagnetic fields are
generated in the trailing shock and provide an emission site. We discuss the
possible implication of our simulation results within the AGN and GRB context.Comment: 4 pages, 3 figures, ApJ Letters, in pres
Measurement of and charged current inclusive cross sections and their ratio with the T2K off-axis near detector
We report a measurement of cross section and the first measurements of the cross section
and their ratio
at (anti-)neutrino energies below 1.5
GeV. We determine the single momentum bin cross section measurements, averaged
over the T2K -flux, for the detector target material (mainly
Carbon, Oxygen, Hydrogen and Copper) with phase space restricted laboratory
frame kinematics of 500 MeV/c. The
results are and $\sigma(\nu)=\left( 2.41\
\pm0.022{\rm{(stat.)}}\pm0.231{\rm (syst.)}\ \right)\times10^{-39}^{2}R\left(\frac{\sigma(\bar{\nu})}{\sigma(\nu)}\right)=
0.373\pm0.012{\rm (stat.)}\pm0.015{\rm (syst.)}$.Comment: 18 pages, 8 figure
Evolution of Global Relativistic Jets: Collimations and Expansion with kKHI and the Weibel Instability
One of the key open questions in the study of relativistic jets is their
interaction with the environment. Here, we study the initial evolution of both
electron-proton and electron-positron relativistic jets, focusing on their
lateral interaction with the ambient plasma. We trace the generation and
evolution of the toroidal magnetic field generated by both kinetic
Kelvin-Helmholtz (kKH) and Mushroom instabilities (MI). This magnetic field
collimates the jet. We show that in electron-proton jet, electrons are
perpendicularly accelerated with jet collimation. The magnetic polarity
switches from the clockwise to anti-clockwise in the middle of jet, as the
instabilities weaken. For the electron-positron jet, we find strong mixture of
electron-positron with the ambient plasma, that results in the creation of a
bow shock. Merger of magnetic field current filaments generate density bumps
which initiate a forward shock. The strong mixing between jet and ambient
particles prevents full development of the jet on the studied scale. Our
results therefore provide a direct evidence for both jet collimation and
particle acceleration in the created bow shock. Differences in the magnetic
field structures generated by electron-proton and electron-positron jets may
contribute to observable differences in the polarized properties of emission by
electrons.Comment: 25 pages, 12 figures, ApJ, accepte
Search for Nucleon Decay into Charged Anti-lepton plus Meson in Super-Kamiokande I and II
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.Comment: 25 pages, 18 figure
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