CNO and pep solar neutrino measurements and perspectives in Borexino

S Davini ,R B Vogelaar ,O Smirnov ,A Razeto ,Andrea Ianni,M Kaiser ,M Agostini ,F Gabriele ,A Romani ,D Bick ,M Goeger-Neff ,L Papp ,J Thurn ,M Laubenstein ,Aldo Ianni,A Goretti ,S Schönert ,C Ghiano ,G Testera ,Y Suvorov ,M Skorokhvatov ,S Appel ,M Gromov ,S Weinz ,G Lukyanchenko ,A Vishneva ,G Bonfini ,D Semenov ,A Chepurnov ,J Winter ,B Caccianiga ,O Zaimidoroga ,G Bellini ,F Von Feilitzsch ,C Galbiati ,M Pallavicini ,M Misiaszek ,M Toropova ,I Machulin ,E Litvinovich ,M Meyer ,E Hungerford ,B Neumair ,V Kobychev ,M Giammarchi ,A Caminata ,H Wang,F Calaprice ,A Re ,L Miramonti ,R Tartaglia ,L Ludhová ,Κ Zuber ,N Rossi ,G Ranucci ,D Korablëv ,G Korga ,M Montuschi ,I Drachnev ,W Maneschg ,L Di Noto ,P Mosteiro ,S Sukhotin ,K Jȩdrzejczak ,E Unzhakov ,V Muratova ,Z Yokley ,D Kryn ,M Obolensky ,A Derbin ,A Etenko ,C Hagner ,B Lehnert ,P Cavalcante ,R Roncin ,A Sotnikov ,K Fomenko ,S Zavatarelli ,S Marcocci ,L Oberauer ,D Bravo ,F Lombardi ,E Meroni ,H Simgen ,A Pocar ,D Franco ,Mariusz Wojcik ,D D’angelo ,F Ortica ,J Benziger ,S Manecki ,M Wurm ,L Perasso ,P Lombardi ,G Zuzel

doi:10.1088/1742-6596/675/1/012040

Abstract

The detection of neutrinos emitted in the CNO reactions in the Sun is one of the ambitious goals of Borexino Phase-II. A measurement of CNO neutrinos would be a milestone in astrophysics, and would allow to solve serious issues in current solar models. A precise measurement of the rate of neutrinos from the pep reaction would allow to investigate neutrino oscillations in the MSW transition region. The pep and CNO solar neutrino physics, the measurement in Borexino Phase-I and the perspectives for the new phase are reviewed in this proceeding.

Highlights

Borexino is a real-time solar neutrino detector that is designed to detect low energy solar neutrinos [1, 2]
First evidence of pep solar neutrinos and limits on CNO solar neutrino flux The Borexino collaboration reported in 2012 the first time measurement of the solar pep neutrino rate and the strongest limits on the CNO solar neutrino flux to date [9]
The detection of pep and CNO solar neutrinos is challenging: their expected interaction rates are a few counts per day in a 100 ton target, and the main backgrounds, the cosmogenic β+-emitter 11C and radiogenic 210Bi, are one order of magnitude more intense [9]

Summary

Introduction

Borexino is a real-time solar neutrino detector that is designed to detect low energy solar neutrinos [1, 2]. After the purification of the scintillator performed between May 2010 and August 2011, in November 2011 the Phase-II of Borexino started. Borexino Phase-I solar neutrino results, described in detail in [2], include a high-precision measurement of 7Be neutrinos [6], the measurement of the absence of day-night asymmetry of 7Be neutrinos [7], a measurement of 8B solar neutrinos with a threshold recoil electron energy of 3 MeV [8], and the first time measurement of pep solar neutrinos and the strongest constraint up to date on CNO solar neutrinos [9].

Results

Conclusion