Improved Measurement of Solar Neutrinos from the Carbon-Nitrogen-Oxygen Cycle by Borexino and Its Implications for the Standard Solar Model

Appel, S.; Bagdasarian, Z.; Basilico, D.; Bellini, G.; Benziger, J.; Biondi, R.; Caccianiga, B.; Calaprice, F.; Caminata, A.; Cavalcante, P.; Chepurnov, A.; D'Angelo, D.; Derbin, A.; Di Giacinto, A.; Di Marcello, V.; Ding, X.  F.; Di Ludovico, A.; Di Noto, L.; Drachnev, I.; Franco, D.; Galbiati, C.; Ghiano, C.; Giammarchi, M.; Goretti, A.; Göttel, A.  S.; Gromov, M.; Guffanti, D.; Ianni, Aldo; Ianni, Andrea; Jany, A.; Kobychev, V.; Korga, G.; Kumaran, S.; Laubenstein, M.; Litvinovich, E.; Lombardi, P.; Lomskaya, I.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Martyn, J.; Meroni, E.; Miramonti, L.; Misiaszek, M.; Muratova, V.; Nugmanov, R.; Oberauer, L.; Orekhov, V.; Ortica, F.; Pallavicini, M.; Papp, L.; Pelicci, L.; Penek, Ö.; Pietrofaccia, L.; Pilipenko, N.; Pocar, A.; Raikov, G.; Ranalli, M.  T.; Ranucci, G.; Razeto, A.; Re, A.; Redchuk, M.; Rossi, N.; Schönert, S.; Semenov, D.; Settanta, G.; Skorokhvatov, M.; Singhal, A.; Smirnov, O.; Sotnikov, A.; Tartaglia, R.; Testera, G.; Unzhakov, E.; Villante, F.  L.; Vishneva, A.; Vogelaar, R.  B.; von Feilitzsch, F.; Wojcik, M.; Wurm, M.; Zavatarelli, S.; Zuber, K.; Zuzel, G.; Null, Null

doi:10.1103/physrevlett.129.252701

We present an improved measurement of the carbon-nitrogen-oxygen (CNO) solar neutrino interaction rate at Earth obtained with the complete Borexino Phase-III dataset. The measured rate, RCNO=6.7-0.8+2.0 counts/(day×100 tonnes), allows us to exclude the absence of the CNO signal with about 7σ C.L. The correspondent CNO neutrino flux is 6.6-0.9+2.0×108 cm-2 s-1, taking into account the neutrino flavor conversion. We use the new CNO measurement to evaluate the C and N abundances in the Sun with respect to the H abundance for the first time with solar neutrinos. Our result of NCN=(5.78-1.00+1.86)×10-4 displays a ∼2σ tension with the "low-metallicity"spectroscopic photospheric measurements. Furthermore, our result used together with the Be7 and B8 solar neutrino fluxes, also measured by Borexino, permits us to disfavor at 3.1σ C.L. the "low-metallicity"standard solar model B16-AGSS09met as an alternative to the "high-metallicity"standard solar model B16-GS98.

Improved Measurement of Solar Neutrinos from the Carbon-Nitrogen-Oxygen Cycle by Borexino and Its Implications for the Standard Solar Model / Appel, S.; Bagdasarian, Z.; Basilico, D.; Bellini, G.; Benziger, J.; Biondi, R.; Caccianiga, B.; Calaprice, F.; Caminata, A.; Cavalcante, P.; Chepurnov, A.; D'Angelo, D.; Derbin, A.; Di Giacinto, A.; Di Marcello, V.; Ding, X. F.; Di Ludovico, A.; Di Noto, L.; Drachnev, I.; Franco, D.; Galbiati, C.; Ghiano, C.; Giammarchi, M.; Goretti, A.; Göttel, A. S.; Gromov, M.; Guffanti, D.; Ianni, Aldo; Ianni, Andrea; Jany, A.; Kobychev, V.; Korga, G.; Kumaran, S.; Laubenstein, M.; Litvinovich, E.; Lombardi, P.; Lomskaya, I.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Martyn, J.; Meroni, E.; Miramonti, L.; Misiaszek, M.; Muratova, V.; Nugmanov, R.; Oberauer, L.; Orekhov, V.; Ortica, F.; Pallavicini, M.; Papp, L.; Pelicci, L.; Penek, Ö.; Pietrofaccia, L.; Pilipenko, N.; Pocar, A.; Raikov, G.; Ranalli, M. T.; Ranucci, G.; Razeto, A.; Re, A.; Redchuk, M.; Rossi, N.; Schönert, S.; Semenov, D.; Settanta, G.; Skorokhvatov, M.; Singhal, A.; Smirnov, O.; Sotnikov, A.; Tartaglia, R.; Testera, G.; Unzhakov, E.; Villante, F. L.; Vishneva, A.; Vogelaar, R. B.; von Feilitzsch, F.; Wojcik, M.; Wurm, M.; Zavatarelli, S.; Zuber, K.; Zuzel, G.; Null, Null. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 129:25(2022), pp. 1-10. [10.1103/physrevlett.129.252701]