Bayesian Constraints on theta_{13} from Solar and KamLAND Neutrino Data

We present the results of a Bayesian analysis of solar and KamLAND neutrino data in the framework of three-neutrino mixing. We adopt two approaches for the prior probability distribution of the oscillation parameters $\Delta{m}^{2}_{21}$, $\sin^{2}\vartheta_{12}$, $\sin^{2}\vartheta_{13}$: 1) a traditional flat uninformative prior; 2) an informative prior which describes the limits on $\sin^{2}\vartheta_{13}$ obtained in atmospheric and long-baseline accelerator and reactor neutrino experiments. In both approaches, we present the allowed regions in the $\sin^{2}\vartheta_{13}$--$\Delta{m}^{2}_{21}$ and $\sin^{2}\vartheta_{12}$--$\sin^{2}\vartheta_{13}$ planes, as well as the marginal posterior probability distribution of $\sin^{2}\vartheta_{13}$. We confirm the hint of $\vartheta_{13}>0$ found in arXiv:0806.2649.