Simultaneous precision spectroscopy of pp, 7Be and pep solar neutrinos with Borexino Phase-II
Phys. Rev. D 100, Issue 8 , 082004 – 15 October 2019
We present the simultaneous measurement of the interaction rates pp, RBe, Rpep of pp, 7Be, and pep solar neutrinos performed with a global fit to the Borexino data in an extended energy range (0.19–2.93) MeV with particular attention to details of the analysis methods. This result was obtained by analyzing 1291.51 days of Borexino Phase-II data, collected after an extensive scintillator purification campaign. Using counts per day (cpd)/100 ton as unit, we find Rpp=134±10(stat)+6−10(sys), RBe=48.3±1.1(stat)+0.4−0.7(sys) and RHZpep=2.43±0.36(stat)+0.15−0.22(sys) assuming the interaction rate RCNO of CNO-cycle (Carbon, Nitrogen, Oxigen) solar neutrinos according to the prediction of the high metallicity standard solar model, and RLZpep=2.65±0.36(stat)+0.15−0.24(sys) according to that of the low metallicity model. An upper limit RCNO<8.1 cpd/100 ton (95% C.L.) is obtained by setting in the fit a constraint on the ratio Rpp/Rpep (47.7±0.8 cpd/100 ton or 47.5±0.8 cpd/100 ton according to the high or low metallicity hypothesis).