Measurement of solar pp neutrino flux using electron recoil data from PandaX-4T commissioning run*

The proton-proton ( ) fusion chain dominates the neutrino production in the Sun. The uncertainty of the predicted neutrino flux is at the sub-percent level, whereas that of the best measurement is (10%). In this study, for the first time, we measure solar neutrinos in the electron recoil energy range from 24 to 144 keV using the PandaX-4T commissioning data with 0.63 tonne year exposure. The neutrino flux is determined as , which is consistent with the Standard Solar Model and existing measurements, corresponding to an upper flux limit of at 90% C.L..