${{\mathit p}}{{\mathit p}}$ solar-neutrino flux measured via ${{\mathit \nu}}{{\mathit e}}$ elastic scattering. This process is sensitive to all active neutrino flavors, but with reduced sensitivity to ${{\mathit \nu}_{{{\mu}}}}$, ${{\mathit \nu}_{{{\tau}}}}$ due to the cross section difference, ${\mathit \sigma (}{{\mathit \nu}}_{{{\mathit \mu}},{{\mathit \tau}}}{{\mathit e}}{)}$ $\sim{}$ 0.3 ${\mathit \sigma (}{{\mathit \nu}_{{{e}}}}{{\mathit e}}{)}$. If the ${{\mathit p}}{{\mathit p}}$ solar-neutrino flux involves nonelectron flavor active neutrinos, their contribution to the flux is $\sim{}$ 0.3 times of ${{\mathit \nu}_{{{e}}}}$.

VALUE ($ 10^{10} $ cm${}^{-2}$ s${}^{-1}$) CL% DOCUMENT ID TECN  COMMENT • • We do not use the following data for averages, fits, limits, etc. • • $<23.3$ 90 1 LU 2024 PNDX average flux $4.4$ $\pm0.5$ 2 BELLINI 2014 A BORX average flux 1  LU 2024 searched for ${{\mathit p}}{{\mathit p}}$ solar neutrinos via ${{\mathit \nu}}{{\mathit e}}$ elastic scattering using PandaX-4T commissioning data. By fitting the measured energy spectrum of events in the $24 - 144$ keV recoil electron kinetic energy, the number of ${{\mathit p}}{{\mathit p}}$ + ${}^{7}\mathrm {Be}$ neutrinos is measured to be $231$ $\pm113$ $\pm287$ events. The ${{\mathit p}}{{\mathit p}}$ neutrino flux is estimated using the expected ratio of ${{\mathit p}}{{\mathit p}}$ to ${}^{7}\mathrm {Be}$ fluxes and their contributions to the measured energy range. 2  BELLINI 2014A reports ${{\mathit p}}{{\mathit p}}$ solar-neutrino flux measured via ${{\mathit \nu}}{{\mathit e}}$ elastic scattering. The data were collected between January 2012 and May 2013, corresponding to 408 days of data. The ${{\mathit p}}{{\mathit p}}$ neutrino interaction rate in Borexino is measured to be $144$ $\pm13$ $\pm10$ counts/(day$\cdot{}$100 ton) by fitting the measured energy spectrum of events in the $165 - 590$ keV recoil electron kinetic energy window with the expected signal + background spectrum. The listed flux value ${{\mathit \phi}_{{{ES}}}}({{\mathit p}}{{\mathit p}}$) is calculated from the observed rate and the number of ($33.07$ $\pm0.03$) $ \times 10^{30}$ electrons for 100 tons of the Borexino scintillator, and the ${{\mathit \nu}_{{{e}}}}{{\mathit e}}$ integrated cross section over the ${{\mathit p}}{{\mathit p}}$ neutrino spectrum, ${\mathit \sigma (}{{\mathit \nu}_{{{e}}}}{{\mathit e}}{)}$ = $11.38 \times 10^{-46}~$cm${}^{2}$.

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