At the Japan Proton Accelerator Research Complex (J-PARC), the world highest intensity secondary beams of kaons, pions, anti-protons, muons, and neutrinos will be produced by irradiating a target ...with the 50
GeV primary proton beam of 0.75
MW. Utilizing such high intensity secondary beams, various unique and interesting experimental studies in nuclear and particle physics can be carried out. We will describe the current R&D status of the target systems to be constructed in the Nuclear and Particle Physics Experimental Hall (NP-Hall) and the neutrino beam line of J-PARC. Some experimental studies proposed there will be also introduced.
The K2K experiment observes indications of neutrino oscillation: a reduction of nu(mu) flux together with a distortion of the energy spectrum. Fifty-six beam neutrino events are observed in ...Super-Kamiokande (SK), 250 km from the neutrino production point, with an expectation of 80.1(+6.2)(-5.4). Twenty-nine one ring mu-like events are used to reconstruct the neutrino energy spectrum, which is better matched to the expected spectrum with neutrino oscillation than without. The probability that the observed flux at SK is explained by statistical fluctuation without neutrino oscillation is less than 1%.
A search for the relic neutrinos from all past core-collapse supernovae was conducted using 1496 days of data from the Super-Kamiokande detector. This analysis looked for electron-type antineutrinos ...that had produced a positron with an energy greater than 18 MeV. In the absence of a signal, 90% C.L. upper limits on the total flux were set for several theoretical models; these limits ranged from 20 to 130 macro nu(e) cm(-2) s(-1). Additionally, an upper bound of 1.2 macro nu(e) cm(-2) s(-1) was set for the supernova relic neutrino flux in the energy region E(nu)>19.3 MeV.
A search for a nonzero neutrino magnetic moment has been conducted using 1496 live days of solar neutrino data from Super-Kamiokande-I. Specifically, we searched for distortions to the energy ...spectrum of recoil electrons arising from magnetic scattering due to a nonzero neutrino magnetic moment. In the absence of a clear signal, we found micro(nu)</=(3.6x10(-10))micro(B) at 90% C.L. by fitting to the Super-Kamiokande day-night spectra. The fitting took into account the effect of neutrino oscillation on the shapes of energy spectra. With additional information from other solar neutrino and KamLAND experiments constraining the oscillation region, a limit of micro(nu)</=(1.1x10(-10))micro(B) at 90% C.L. was obtained.
We carried out intraoperative monitoring of the pudental nerve while separating vertebral spinal tumors from the spinal cord in five patients, including four infants. Although monitoring using a ...manometer or needle electrodes has been reported, monitoring done with disk electrodes to ascertain the compound muscle action potential (CMAP) of the external sphincter muscle has not been yet attempted. Prior to the surgical procedure, we locate a point suitable for CAMP recording of the muscle. In our recent study, we determined that maximum action potentials were recorded in the part with the greatest depth from the individual anal verge. Therefore, the depth of the anal canal was preoperatively measured for the manometry method, and sphincter electrodes currently on the market were refigured to suit the infant's anal canal. After the two procedures described above, we were able to preserve the pudental nerves intraoperatively. The postoperative neurological findings of all five patients were unchanged. We introduce here this new method of intraoperative monitoring for preserving the pudental nerve.
We present the results of a search for low energy nu(e) from the Sun using 1496 days of data from Super-Kamiokande-I. We observe no significant excess of events and set an upper limit for the ...conversion probability to nu(e) of the 8B solar neutrino. This conversion limit is 0.8% (90% C.L.) of the standard solar model's neutrino flux for total energy=8-20 MeV. We also set a flux limit for monochromatic nu(e) for E(nu(e))=10-17 MeV.
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