Resolving the neutrino mass hierarchy and CP degeneracy by two identical detectors with different baselines

We explore the possibility of the simultaneous determination of neutrino mass hierarchy and the CP violating phase by using two identical detectors placed at different baseline distances. We focus on a possible experimental setup using a neutrino beam from the J-PARC facility in Japan with a beam power of 4 MW and megaton (Mton)-class water Cherenkov detectors, one placed in Kamioka and the other somewhere in Korea. We demonstrate, under reasonable assumptions of systematic uncertainties, that the two-detector complex with each fiducial volume of 0.27 Mton has a potential of resolving the neutrino mass hierarchy up to sin{sup 2}2{theta}{sub 13}>0.03 (0.055) at 2{sigma} (3{sigma}) C.L. for any values of {delta} and at the same time has the sensitivity to CP violation by 4+4 years running of {nu}{sub e} and {nu}{sub e} appearance measurement. The significantly enhanced sensitivity is due to clean detection of the modulation of the neutrino energy spectrum, which is enabled by the cancellation of systematic uncertainties between two identical detectors which receive the neutrino beam with the same energy spectrum in the absence of oscillations.