Improved measurement of B8 solar neutrinos with 1.5 kt·y of Borexino exposure

• DOI: 10.1103/physrevd.101.062001
• Publication Date: 2020-03-09T13:57:47Z
• Authors: M. Agostini; K. Altenmüller; S. Appel; V. Atroshchenko; Z. Bagdasarian; D. Basilico; G. Bellini; J. Benziger; D. Bick; D. Bravo; B. Caccianiga; F. Calaprice; A. Caminata; P. Cavalcante; A. Chepurnov; D. D’Angelo; S. Davini; A. Derbin; A. Di Giacinto; V. Di Marcello; X. F. Ding; A. Di Ludovico; L. Di Noto; I. Drachnev; A. Formozov; D. Franco; C. Galbiati; M. Gschwender; C. Ghiano; M. Giammarchi; A. Goretti; M. Gromov; D. Guffanti; C. Hagner; T. Houdy; E. Hungerford; Aldo Ianni; Andrea Ianni; A. Jany; D. Jeschke; V. Kobychev; G. Korga; S. Kumaran; T. Lachenmaier; M. Laubenstein; E. Litvinovich; P. Lombardi; I. Lomskaya; L. Ludhova; G. Lukyanchenko; L. Lukyanchenko; I. Machulin; S. Marcocci; J. Martyn; E. Meroni; M. Meyer; L. Miramonti; M. Misiaszek; V. Muratova; B. Neumair; M. Nieslony; R. Nugmanov; L. Oberauer; V. Orekhov; F. Ortica; M. Pallavicini; L. Papp; Ö. Penek; L. Pietrofaccia; N. Pilipenko; A. Pocar; G. Raikov; M. T. Ranalli; G. Ranucci; A. Razeto; A. Re; M. Redchuk; A. Romani; N. Rossi; S. Rottenanger; S. Schönert; D. Semenov; M. Skorokhvatov; O. Smirnov; A. Sotnikov; Y. Suvorov; R. Tartaglia; G. Testera; J. Thurn; E. Unzhakov; A. Vishneva; R. B. Vogelaar; F. von Feilitzsch; M. Wojcik; M. Wurm; S. Zavatarelli; K. Zuber; G. Zuzel
• Keywords: Borexino

We report on an improved measurement of the $^{8}\mathrm{B}$ solar neutrino interaction rate with Borexino experiment at Laboratori Nazionali del Gran Sasso. Neutrinos are detected via their elastic scattering electrons in a large volume liquid scintillator. The measured scattered above 3 MeV energy is ${0.223}_{\ensuremath{-}0.016}^{+0.015}(\mathrm{stat}){\text{ }}_{\ensuremath{-}0.006}^{+0.006}(\mathrm{syst})\text{ }\text{ }\mathrm{cpd}/100\text{ }\mathrm{t}$, which corresponds to observed flux assuming no flavor conversion ${\mathrm{\ensuremath{\Phi}}}_{^{8}\mathrm{B}}^{\mathrm{ES}}=2.5{7}_{\ensuremath{-}0.18}^{+0.17}(\mathrm{stat}){\text{ }}_{\ensuremath{-}0.07}^{+0.07}(\mathrm{syst})\ifmmode\times\else\texttimes\fi{}{10}^{6}\text{ }{\mathrm{cm}}^{\ensuremath{-}2}\text{ }{\mathrm{s}}^{\ensuremath{-}1}$. This exploits active detector almost its entirety for first time, and takes advantage reduced radioactive background following 2011 scintillator purification campaign novel analysis tools providing more precise modeling background. Additionally, we set new limit hep neutrinos, searched as well neutral current-mediated inelastic carbon, $^{12}\mathrm{C}(\ensuremath{\nu},{\ensuremath{\nu}}^{\ensuremath{'}})^{12}{\mathrm{C}}^{*}$ (${E}_{\ensuremath{\gamma}}=15.1\text{ }\mathrm{MeV}$).