The T2K ND280 Off-Axis Pi-Zero Detector

The Pi-Zero detector (P{\O}D) is one of the subdetectors that makes up the off-axis near detector for the Tokai-to-Kamioka (T2K) long baseline neutrino experiment. The primary goal for the P{\O}D is to measure the relevant cross sections for neutrino interactions that generate pi-zero's, especially the cross section for neutral current pi-zero interactions, which are one of the dominant sources of background to the electron neutrino appearance signal in T2K. The P{\O}D is composed of layers of plastic scintillator alternating with water bags and brass sheets or lead sheets and is one of the first detectors to use Multi-Pixel Photon Counters (MPPCs) on a large scale.Comment: 17 pages, submitted to NIM

Correlations and Fluctuations in High-Energy Nuclear Collisions

Nucleon correlations in the target and projectile nuclei are shown to reduce significantly the fluctuations in multiple nucleon-nucleon collisions, total multiplicity and transverse energy in relativistic heavy-ion collisions, in particular for heavy projectile and target. The interplay between cross-section fluctuations, from color transparency and opacity, and nuclear correlations is calculated and found to be able to account for large fluctuations in transverse energy spectra. Numerical implementation of correlations and cross-section fluctuations in Monte-Carlo codes is discussed.Comment: 30 pages, in Revtex, plus 4 figures. Figures and preprint can be obtained by mailing address to: [email protected]

Measurement of single pi0 production in neutral current neutrino interactions with water by a 1.3 GeV wide band muon neutrino beam

Neutral current single pi0 production induced by neutrinos with a mean energy of 1.3 GeV is measured at a 1000 ton water Cherenkov detector as a near detector of the K2K long baseline neutrino experiment. The cross section for this process relative to the total charged current cross section is measured to be 0.064 +- 0.001 (stat.) +- 0.007 (sys.). The momentum distribution of produced pi0s is measured and is found to be in good agreement with an expectation from the present knowledge of the neutrino cross sections.Comment: 6 pages, 4 figures, Submitted to Phys. Lett.

Calibration of Super-Kamiokande Using an Electron Linac

In order to calibrate the Super-Kamiokande experiment for solar neutrino measurements, a linear accelerator (LINAC) for electrons was installed at the detector. LINAC data were taken at various positions in the detector volume, tracking the detector response in the variables relevant to solar neutrino analysis. In particular, the absolute energy scale is now known with less than 1 percent uncertainty.Comment: 24 pages, 16 figures, Submitted to NIM

Measurement of radon concentrations at Super-Kamiokande

Radioactivity from radon is a major background for observing solar neutrinos at Super-Kamiokande. In this paper, we describe the measurement of radon concentrations at Super-Kamiokande, the method of radon reduction, and the radon monitoring system. The measurement shows that the current low-energy event rate between 5.0 MeV and 6.5 MeV implies a radon concentration in the Super-Kamiokande water of less than 1.4 mBq/m$^3$.Comment: 11 pages, 4 figure

Search for Neutral Q-balls in Super-Kamiokande II

A search for Q-balls induced groups of successive contained events has been carried out in Super-Kamiokande II with 541.7 days of live time. Neutral Q-balls would emit pions when colliding with nuclei, generating a signal of successive contained pion events along a track. No candidate for successive contained event groups has been found in Super-Kamiokande II, so upper limits on the possible flux of such Q-balls have been obtained.Comment: 5 pages, 5 figures, Submitted to Phys. Lett.

Evidence for muon neutrino oscillation in an accelerator-based experiment

We present results for muon neutrino oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced muon neutrino beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy dependent disappearance of muon neutrino, which we presume have oscillated to tau neutrino. The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma).Comment: 5 pages, 4 figure

Raining in MKW 3 s: a Chandra-MUSE analysis of X-Ray cold filaments around 3CR 318.1

High Energy Astrophysic

Fragmentation and Multifragmentation of 10.6A GeV Gold Nuclei

We present the results of a study performed on the interactions of 10.6A GeV gold nuclei in nuclear emulsions. In a minimum bias sample of 1311 interac- tions, 5260 helium nuclei and 2622 heavy fragments were observed as Au projec- tile fragments. The experimental data are analyzed with particular emphasis of target separation interactions in emulsions and study of criticalexponents. Multiplicity distributions of the fast-moving projectile fragments are inves- tigated. Charged fragment moments, conditional moments as well as two and three -body asymmetries of the fast moving projectile particles are determined in terms of the total charge remaining bound in the multiply charged projectile fragments. Some differences in the average yields of helium nuclei and heavier fragments are observed, which may be attributed to a target effect. However, two and three-body asymmetries and conditional moments indicate that the breakup mechanism of the projectile seems to be independent of target mass. We looked for evidence of critical point observable in finite nuclei by study the resulting charged fragments distributions. We have obtained the values for the critical exponents gamma, beta and tau and compare our results with those at lower energy experiment (1.0A GeV data). The values suggest that a phase transition like behavior, is observed.Comment: latex, revtex, 28 pages, 12 figures, 3tables, submitted to Europysics Journal