KamLAND has measured the flux of nu;(e)'s from distant nuclear reactors. We find fewer nu;(e) events than expected from standard assumptions about nu;(e) propagation at the 99.95% C.L. In a 162 ton.yr exposure the ratio of the observed inverse beta-decay events to the expected number without nu;(e) disappearance is 0.611+/-0.085(stat)+/-0.041(syst) for nu;(e) energies >3.4 MeV. In the context of two-flavor neutrino oscillations with CPT invariance, all solutions to the solar neutrino problem except for the "large mixing angle" region are excluded.

We review and analyze the available information on the nuclear-fusion cross sections that are most important for solar energy generation and solar neutrino production. We provide best values for the low-energy cross-section factors and, wherever possible, estimates of the uncertainties. We also describe the most important experiments and calculations that are required in order to improve our knowledge of solar fusion rates. [S0034-6861(98)00704-1]

We present a systematic evaluation of the shape of the neutrino energy spectrum produced by beta-decay of 8 B. We place special emphasis on determining the range of uncertainties permitted by existing laboratory data and theoretical ingredients (such as forbidden and radiative corrections). We review and compare the available experimental data on the 8 B(β + ) 8 Be(2α) decay chain. We analyze the theoretical and experimental uncertainties quantitatively. We give a numerical representation of the best-fit (standard-model) neutrino spectrum, as well as two extreme deviations from the standard spectrum that represent the total (experimental and theoretical) effective ±3σ deviations. Solar neutrino experiments that are currently being developed will be able to measure the shape of the 8 B neutrino spectrum above about 5 MeV. An observed distortion of the 8 B solar neutrino spectrum outside the range given

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A systematic study of the inclusive (0ν + 2ν) double beta (ββ) decay of 100 Mo to various excited final states of 100 Ru was performed. Utilizing two large HPGe detectors operated in coincidence, a search for the subsequent deexcitation γγ cascades was conducted. A 1.05-kg sample of isotopically enriched (98.4%) 100 Mo was investigated for 455 days, yielding an unambiguous observation of the ββ decay of 100 Mo to the 0 + 1 state (1130.3 keV) of 100 Ru. This excited final state decays via the 0 + 1 → 2 + 1 → 0 + gs sequence (with Eγ1 = 590.8 keV and Eγ2 = 539.5 keV), and 22 such coincidence events were detected, with a continuous background estimated to be 2.5 events. This counting rate corresponds to a decay half-life for the ββ(0 + → 0 + 1 ) transition of T (0ν+2ν) 1/2 = 6.0 +1.9 −1.1 (stat) ± 0.6(syst) × 10 20 years. Lower limits on decay half-lives were achieved for higher excited final states.