Neutrino oscillations at low energy long baseline experiments in the presence of nonstandard interactions and parameter degeneracy

We discuss the analytical expression of the oscillation probabilities at low energy long baseline experiments, such as Tokai to HyperKamiokande (T2HK) and Tokai to HyperKamioka and Korea (T2HKK), in the presence of nonstandard interactions (NSIs). We show that these experiments are advantageous in the exploration of the NSI parameters ($\epsilon_D$, $\epsilon_N$), which were suggested to be nonvanishing to account for the discrepancy between the solar neutrino and Kamioka Liquid scintillator Anti-Neutrino Detector data. We also show that, when the NSI parameters are small, parameter degeneracy in the CP phase $\delta$, $\epsilon_D$ and $\epsilon_N$ can be resolved by combining data of the T2HK and T2HKK experiments.