First evidence of pep solar neutrinos by direct detection in Borexino

C. Galbiati, G. Bellini, J. Benziger, D. Bick, S. Bonetti, G. Bonfini, D. Bravo, M. Buizza Avanzini, B. Caccianiga, L. Cadonati, F. Calaprice, C. Carraro, P. Cavalcante, A. Chavarria, D. Dangelo, S. Davini, A. Derbin, A. Etenko, K. Fomenko, D. FrancoC. Galbiati, S. Gazzana, C. Ghiano, M. Giammarchi, M. Goeger Neff, A. Goretti, L. Grandi, E. Guardincerri, S. Hardy, Aldo Ianni, Andrea Ianni, D. Korablev, G. Korga, Y. Koshio, D. Kryn, M. Laubenstein, T. Lewke, E. Litvinovich, B. Loer, F. Lombardi, P. Lombardi, L. Ludhova, I. MacHulin, S. Manecki, W. Maneschg, G. Manuzio, Q. Meindl, E. Meroni, L. Miramonti, M. Misiaszek, D. Montanari, P. Mosteiro, V. Muratova, L. Oberauer, M. Obolensky, F. Ortica, K. Otis, M. Pallavicini, L. Papp, L. Perasso, S. Perasso, A. Pocar, J. Quirk, R. S. Raghavan, G. Ranucci, A. Razeto, A. Re, A. Romani, A. Sabelnikov, R. Saldanha, C. Salvo, S. Schönert, H. Simgen, M. Skorokhvatov, O. Smirnov, A. Sotnikov, S. Sukhotin, Y. Suvorov, R. Tartaglia, G. Testera, D. Vignaud, R. B. Vogelaar, F. Von Feilitzsch, J. Winter, M. Wojcik, A. Wright, M. Wurm, J. Xu, O. Zaimidoroga, S. Zavatarelli, G. Zuzel

Research output: Contribution to journalConference article

2 Scopus citations

Abstract

We observed, for the first time, solar neutrinos in the 1.0-1.5 MeV energy range. We determined the rate of pep solar neutrino interactions in Borexino to be 3.l±0.6stat±0.3syst counts/(day-100 ton). Assuming the pep neutrino flux predicted by the Standard Solar Model, we obtained a constraint on the CNO solar neutrino interaction rate of <7.9 counts/(day-100 ton) (95% C.L.). The absence of the solar neutrino signal is disfavored at 99.97% C.L., while the absence of the pep signal is disfavored at 98% C.L. The necessary sensitivity was achieved by adopting data analysis techniques for the rejection of cosmogenic 11C, the dominant background in the 1-2 MeV region. Assuming the MSW-LMA solution to solar neutrino oscillations, these values correspond to solar neutrino fluxes of (1.6±0.3)×l08cm-2s-1 and <7.7×l08 cm-2s-1 (95% C.L.), respectively, in agreement with both the High and Low Metallicity Standard Solar Models. These results represent the first direct evidence of the pep neutrino signal and the strongest constraint of the CNO solar neutrino flux to date.

Original languageEnglish (US)
Article number042030
JournalJournal of Physics: Conference Series
Volume375
Issue numberPART 4
DOIs
StatePublished - 2012
Event12th International Conference on Topics in Astroparticle and Underground Physics, TAUP 2011 - Munich, Germany
Duration: Sep 5 2011Sep 9 2011

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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    Galbiati, C., Bellini, G., Benziger, J., Bick, D., Bonetti, S., Bonfini, G., Bravo, D., Avanzini, M. B., Caccianiga, B., Cadonati, L., Calaprice, F., Carraro, C., Cavalcante, P., Chavarria, A., Dangelo, D., Davini, S., Derbin, A., Etenko, A., Fomenko, K., ... Zuzel, G. (2012). First evidence of pep solar neutrinos by direct detection in Borexino. Journal of Physics: Conference Series, 375(PART 4), [042030]. https://doi.org/10.1088/1742-6596/375/1/042030