MeasuringCPviolation and mass ordering in joint long baseline experiments with superbeams

We propose to measure the $\mathrm{CP}$ phase ${\delta }_{\mathrm{CP}},$ the magnitude of the neutrino mixing matrix element $|U_{e3\mathrm{}}|$ and the sign of the atmospheric scale mass-squared difference $\Delta {\mathrm{m}}_{31}^2$ with a superbeam by the joint analysis of two different long baseline neutrino oscillation experiments. One is a long baseline experiment (LBL) at 300 km and the other is a very long baseline (VLBL) experiment at 2100 km. We take the neutrino source to be the approved high intensity proton synchrotron, HIPA. The neutrino beam for the LBL is the 2-degree off-axis superbeam, and for the VLBL a narrowband superbeam. Taking into account all possible errors, we evaluate the event rates required and the sensitivities that can be attained for the determination of ${\delta }_{\mathrm{CP}}$ and the sign of $\Delta m_{31}^2.$ We arrive at a representative scenario for a reasonably precise probe of this part of neutrino physics.