Synergies between the first - generation JHF - SK and NuMI superbeam experiments ∗

We discuss synergies in the combination of the first-generation JHF to Super-Kamiokande and NuMI off-axis superbeam experiments. With synergies we mean effects which go beyond simply adding the statistics of the two experiments. As a first important result, we do not observe interesting synergy effects in the combination of the two experiments as they are planned right now. However, we find that with minor modifications, such as a different NuMI baseline or a partial antineutrino running, one could do much richer physics with both experiments combined. Specifically, we demonstrate that one could, depending on the value of the solar mass squared difference, either measure the sign of the atmospheric mass squared difference or CP violation already with the initial stage experiments. Our main results are presented in a way that can be easily interpreted in terms of the forthcoming KamLAND result.