Search for dinucleon decay into kaons in Super-Kamiokande.

A search for the dinucleon decay pp → K+ K+ has been performed using 91.6 kton·yr data from Super-Kamiokande-I. This decay provides a sensitive probe of the R-parity-violating parameter λ112''. A boosted decision tree analysis found no signal candidates in the data. The expected background was 0.28±0.19 atmospheric neutrino induced events and the estimated signal detection efficiency was 12.6%±3.2%. A lower limit of 1.7×10(32) years has been placed on the partial lifetime of the decay O16 → C14K+ K+ at 90% C.L. A corresponding upper limit of 7.8×10(-9) has been placed on the parameter λ112''.

Search for Lorentz invariance and CPT violation with the MINOS far detector.

We searched for a sidereal modulation in the MINOS far detector neutrino rate. Such a signal would be a consequence of Lorentz and CPT violation as described by the standard-model extension framework. It also would be the first detection of a perturbative effect to conventional neutrino mass oscillations. We found no evidence for this sidereal signature, and the upper limits placed on the magnitudes of the Lorentz and CPT violating coefficients describing the theory are an improvement by factors of 20-510 over the current best limits found by using the MINOS near detector.

Search for proton decay via p-->e+pi0 and p-->micro+pi0 in a large water Cherenkov detector.

We have searched for proton decays via p-->e;{+}pi;{0} and p-->micro;{+}pi;{0} using data from a 91.7 kt.yr exposure of Super-Kamiokande-I and a 49.2 kt.yr exposure of Super-Kamiokande-II. No candidate events were observed with expected backgrounds induced by atmospheric neutrinos of 0.3 events for each decay mode. From these results, we set lower limits on the partial lifetime of 8.2 x 10;{33} and 6.6 x 10;{33} years at 90% confidence level for p-->e;{+}pi;{0} and p-->micro;{+}pi;{0} modes, respectively.

Measurement of atmospheric neutrino flux consistent with tau neutrino appearance.

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.

Limits on the neutrino magnetic moment using 1496 days of Super-Kamiokande-I solar neutrino data.

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)

Evidence for an oscillatory signature in atmospheric neutrino oscillations.

Muon neutrino disappearance probability as a function of neutrino flight length L over neutrino energy E was studied. A dip in the L/E distribution was observed in the data, as predicted from the sinusoidal flavor transition probability of neutrino oscillation. The observed L/E distribution constrained nu(micro)<-->nu(tau) neutrino oscillation parameters; 1.9x10(-3)0.90 at 90% confidence level.