Global analysis of solar neutrino and KamLAND data

A global analysis of the data from all the solar neutrino experiments combined with the recent KamLAND data is presented. A formula frequently used in the literature gives survival probability for three active solar neutrino flavours in terms of a suitably modified two-flavour survival probability. Corrections to this formula, which depend on θ 13 and δ m 2 31 , are calculated. For the mass scale suggested by the atmospheric neutrino experiments the contributions of δ m 2 31 to these corrections are found to be negligible. The role of θ 13 in solar neutrino physics is elaborated. For electron neutrino oscillations into another active flavour, we find best fit values of tan 2 θ 12 ∼ 0.46, tan 2 θ 13 ∼ 0 and δ m 2 21 ∼ 7.1 × 10 −5 eV 2 . It is found that the combined solar neutrino and KamLAND data provide the limit cos 4 θ 13 > 0.8 at the 90% confidence level.