LMA MSW solution of the solar neutrino problem and first KamLAND results

The first KamLAND results are shown to be in very good agreement with the predictions made on the basis of the solar neutrino data and the LMA realization of the MSW mechanism. We perform a combined analysis of the KamLAND (rate, spectrum) and the solar neutrino data with a free boron neutrino flux f(B). The best fit values of neutrino parameters are Deltam(2) = 7.3 x 10(-5) eV(2), tan(2) theta = 0.41 and f(B) = 1.05 with the 1sigma intervals: Deltam(2) = (6.2-8.4) x 10(-5) eV(2), tan(2) theta = 0.33-0.54. We find the 3sigma upper bounds: Deltam(2) < 2.8 x 10(-4) eV(2) and tan(2) theta < 0.84, and the lower bound Deltam(2) > 4 x 10(-5) eV(2). At 99% CL the KamLAND spectral result splits the LMA region into two parts with the preferred one at Deltam(2) < 10(-4) eV(2). The higher Delta m(2) region is accepted at about the 2 sigma level. We show that effects of non-zero 13-mixing, sin(2) theta(13) <= 0.04, are small, leading to a slight improvement of the fit in the higher Delta m(2) region. At the best fit point we predict for SNO: CC/NC = 0.33(-0.03)(+0.05) and A(DN)(SNO) = 2.8 +/- 0.8% (68% CL), and A(DN)(SNO) < 9% at the 3 sigma level. Further improvements in the determination of the oscillation parameters are discussed and implications of the solar neutrino and KamLAND results are considered.