DUNE as the Next-Generation Solar Neutrino Experiment

We show that the Deep Underground Neutrino Experiment (DUNE), with significant but feasible new efforts, has the potential to deliver world-leading results in solar neutrinos. With a 100 kton-year exposure, DUNE could detect $\gtrsim 10^5$ signal events above 5 MeV electron energy. Separate precision measurements of neutrino-mixing parameters and the $^8$B flux could be made using two detection channels ($ν_e + \, ^{40}$Ar and $ν_{e,μ,τ} + e^-$) and the day-night effect ($> 10 σ$). New particle physics may be revealed through the comparison of solar neutrinos (with matter effects) and reactor neutrinos (without), which is discrepant by $\sim 2 σ$ (and could become $5.6 σ$). New astrophysics may be revealed through the most precise measurement of the $^8$B flux (to 2.5\%) and the first detection of the {\it hep} flux (to 11\%). {\it DUNE is required:} No other experiment, even proposed, has been shown capable of fully realizing these discovery opportunities.