Non-standard interactions from the future neutrino solar sector

The next-generation neutrino experiment JUNO will determine the solar oscillation parameters - $\sin^2 \theta_{12}$ and $\Delta m^2_{21}$ - with great accuracy, in addition to measuring $\sin^2\theta_{13}$, $\Delta m^2_{31}$, and the mass ordering. In parallel, the continued study of solar neutrinos at Hyper-Kamiokande will provide complementary measurements in the solar sector. In this paper, we address the expected sensitivity to non-universal and flavour-changing non-standard interactions (NSI) with $d$-type quarks from the combination of these two future neutrino experiments. We also show the robustness of their measurements of the solar parameters $\sin^2 \theta_{12}$ and $\Delta m^2_{21}$ in the presence of NSI. We study the impact of the exact experimental configuration of the Hyper-Kamiokande detector, and conclude it is of little relevance in this scenario. Finally, we find that the LMA-D solution is expected to be present if no additional input from non-oscillation experiments is considered.