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Abstract:

The Sudbury Neutrino Observatory is a 1000 T D2O Cerenkov detector that is sensitive to B-8 solar neutrinos. The energy, radius, and direction with respect to the sun is Measured for each neutrino event; these distributions are used to separately determine the rates of the charged current, neutral current and electron scattering reactions of neutrinos on deuterium. Assuming an undistorted B-8 spectrum, the nu(e) component of the B-8 solar flux is phi(e) = 1.76(-0.05)(+0.05) (stat.)(-0.09)(+0.09) (syst.) X 10(6) cm(-2)s(-1) based on events with a measured kinetic energy above 5 MeV. The non-nu(e) component is phi(mutau) = 3.41(-0.45)(+0.45)(stat.)(-0.45)(+0.48) (syst.) X 10(6) cm(-2)s(-1), 5.3sigma greater than zero, providing strong evidence for solar nu(e) flavor transformation. The total flux measured with the NC reaction is phi(NC) = 5.09(-0.43)(+0.44) (stat.)(-0.43)(+0.46) (syst.) X 10(6) cm(-2)s(-1), consistent with solar models. The night minus day rate is 14.0% +/- 6.3%(+1.5)(-1.4)% of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the nu(e) asymmetry is found to be 7.0% +/- 4.9%(+1.3)(-1.2)%. A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the Large Mixing Angle (LMA) solution.

Abstract:

With the evidence for massive neutrinos from recent ν-oscillation experiments, one of the most fundamental tasks of particle physics over the next years will be the determination of the absolute mass scale of neutrinos, which has crucial implications for cosmology, astrophysics and particle physics. The KArlsruhe TRItium Neutrino (KATRIN) experiment is the next-generation direct neutrino mass experiment with a sensitivity to sub-eV ν-masses. It combines an ultra-luminous molecular windowless gaseous tritium source with a high resolution electrostatic retarding spectrometer (MAC-E filter) to measure the spectral shape of β-decay electrons close to the endpoint at 18.6 keV with unprecedented precision. If no neutrino mass signal is found, the KATRIN sensitivity after 3 years of measurements is mν < 0.2 eV/c2 (90 % CL.); a ν-mass signal of mν = 0.35 (0.30) eV/c2 can be measured with 5 (3) σ evidence.

Abstract:

The solar neutrino capture rate measured by the Russian-American Gallium Experiment on a metallic gallium target SAGE during the time from January 1990 through December 2000 is 77.0-6.2-3.0^+6.2+3.5 SNU, where the uncertainties are statistical and systematic, respectively. The experimental procedures and data analysis are presented. © 2002 MAIK. "Nauka/Interperiodica".