The measurement of θ₁₃ and δ: the role of the uncertainties on the solar and atmospheric parameters

In this talk we show how the errors on solar and atmospheric parameters affect the measurement of the unknown PMNS parameters $\theta_{13}$ and $\delta$ at future LBL facilities. Performing three parameters fits in $\theta_{13}$, $\delta$ and, in turn, one of the atmospheric or solar parameters, we show that present uncertainties on $\theta_{23}$ and $\Delta m^2_{23}$ worsen significantly the precision on ($\theta_{13}$,$\delta$) whereas the solar sector does not introduce further uncertainties. A precision on the atmospheric parameters similar to what expected at T2K-I is necessary to improve the sensitivities to $\theta_{13}$ and $\delta$.