Cornering solar radiative-zone fluctuations with KamLAND and SNO salt

We update the best constraints on fluctuations in the solar medium deep within the solar radiative zone to include the new SNO salt solar neutrino measurements. We find that these new measurements are now sufficiently precise that neutrino-oscillation parameters can be inferred independently of any assumptions about fluctuation properties. Constraints on fluctuations are also improved, with amplitudes of 5% now excluded at the 99% confidence level for correlation lengths in the range of a few hundred kilometres. Because they are sensitive to correlation lengths which are so short, these solar neutrino results are complementary to constraints coming from helioseismology.