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Expected prompt visible energy spectra of the CC signal and backgrounds after the optimized cuts. The accidental background with the recoiled electron from solar neutrino ES interaction as the prompt signal is illustrated as the green line. The background from muon-induced isotopes is illustrated as the red line, which is the summation of the accidental and correlated backgrounds originated from the initial muons.
Expected visible energy spectra of all single event sources for 10 years of data taking with the same energy-dependent fiducial volume cuts as in Ref.~\cite{JUNO:2020hqc} are illustrated. The blue and green curves are singles from the $\nu_x+^{13}{\rm C}$ NC and $\nu_x+e$ ES channels, respectively. The purple curve includes the $\nu_e+^{13}{\rm C}\rightarrow e^-+^{13}{\rm N}\,(\frac{3}{2}^{-})$ channel and the residual singles of the $\nu_e+^{13}{\rm C}\rightarrow e^-+^{13}{\rm N}\,(\frac{1}{2}^{-})$ channel after the coincidence cut. The red curve represents the single events from natural radioactivity and muon-induced unstable isotopes. The brown curve includes the $\Bar{\nu}_e+e$ ES and $\Bar{\nu}_x+^{13}{\rm C}$ NC channels from reactor antineutrinos. The black curve is the summation of all the components. The upper right insert plot is illustrated for the energy range between 3 and 5 MeV in the linear scale. Note that the discontinuities at 3 MeV and 5 MeV are due to the changes in the fiducial volume size.
Ratios of the solar neutrino signal event rates with and without considering terrestrial matter effects as the function of the zenith angle for the ES (red sold line) and CC (blue solid line) channels. The dashed lines are shown for the average over the whole zenith angle range. The ratios for the daytime, nighttime and the day-night average are also shown for comparison. The blue shaded regions with different colors from the left to right are used to denote the zenith angle ranges passing through the crust, mantle and core of the Earth. Note that the signal rate in the night is higher than that in the day due to the $\nu_e$ regeneration through the Earth.
Comparison of the sensitivity on the $^{8}$B solar neutrino flux, sin$^2\theta_{12}$ and $\Delta m^2_{21}$ between the ES measurement (single events outside [3.5, 4.1] MeV) and the ES+NC measurement (all singles events). The 1$\sigma$ (68.3\%), 2$\sigma$ (95.5\%), and 3$\sigma$ (99.7\%) allowed regions are illustrated with blue lines and red shaded regions, respectively. The marginalized projections of these parameters are also shown.
Same as Fig.~\ref{fig:2d1}, but for the comparison between the ES+NC measurement (all single events) and the ES+NC+CC measurement (both the single events and correlated events).
Same as Fig.~\ref{fig:2d1}, but for the comparison between the ES+NC+CC measurement of JUNO and the combined JUNO+SNO flux measurement.
Relative uncertainties of the $^8$B solar neutrino flux (left panel), $\Delta m^2_{21}$ (middle panel), and $\sin^2\theta_{12}$ (right panel) from the model independent approach with different combinations of the data sets. The colored bands in the left panel are for the flux uncertainty from the SSM~\cite{Vinyoles:2016djt}, the NC measurement of the SNO Phase-III data (SNO-NC)~\cite{SNO:2011ajh}, and the combined SNO CC, NC and ES data (SNO)~\cite{SNO:2011hxd}. The green bands in the middle and right panels are the uncertainty of oscillation parameters from the combined SK and SNO solar neutrino data~\cite{yasuhiro_nakajima_2020_4134680}.