Measurement of Solar $pp$ Neutrino Flux using Electron Recoil Data from PandaX-4T Commissioning Run

TL;DR

This study reports the first measurement of solar $pp$ neutrino flux using electron recoil data from PandaX-4T, achieving a result consistent with the Standard Solar Model and prior measurements, with a new upper limit established.

Contribution

First measurement of solar $pp$ neutrino flux using electron recoil data from PandaX-4T with 0.63 tonne-year exposure.

Findings

Measured $pp$ neutrino flux: (8.0 ± 3.9 (stat) ± 10.0 (syst))×10^{10} s^{-1}cm^{-2}

Flux consistent with Standard Solar Model and previous measurements

Established a 90% C.L. upper limit of 23.3×10^{10} s^{-1}cm^{-2}

Abstract

The proton-proton ($pp$) fusion chain dominates the neutrino production from the Sun. The uncertainty of the predicted $pp$ neutrino flux is at the sub-percent level, whereas that of the best measurement is $\mathcal{O}(10\%)$. In this paper, we present the first result to measure the solar $pp$ neutrinos in the electron recoil energy range from 24 to 144 keV, using the PandaX-4T commissioning data with 0.63 tonne$\times$year exposure. The $pp$ neutrino flux is determined to be $(8.0 \pm 3.9 \,{\rm{(stat)}} \pm 10.0 \,{\rm{(syst)}} )\times 10^{10}\, $$\rm{s}^{-1} \rm{cm}^{-2}$, consistent with Standard Solar Model and existing measurements, corresponding to a flux upper limit of $23.3\times 10^{10}\, $$\rm{s}^{-1} \rm{cm}^{-2}$ at 90\% C.L..