Effect of sterile phases on degeneracy resolution capabilities of LBL experiments

In sterile neutrino (3+1) parameterisation, we observe that sterile phases ($\delta_{14},\delta_{24}$) are always together in oscillation probability, even when the MSW effect is considered. We see that the difference between the sterile phases has a more dominating effect over event rates compared to small variations due to changes in individual values. In this work, we show the value of sterile phase difference ($\delta_{14}-\delta_{24}$) that least affects the parameter degeneracy resolution of $\delta_{13},\theta_{23}$ at long-baseline experiments.