Precision measurement of the 7Be solar neutrino interaction rate in ...

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Aug 24, 2011 - (1998); J.P. Cravens et al. (SuperKamiokaNDE Collabo- ration), Phys. Rev. D 78, 032002 (2008). [4] Q.R. Ahmad et al. (SNO Collaboration) ...
arXiv:1104.1816v2 [hep-ex] 24 Aug 2011

Precision measurement of the 7 Be solar neutrino interaction rate in Borexino G. Bellini,1 J. Benziger,2 D. Bick,3 S. Bonetti,1 G. Bonfini,4 M. Buizza Avanzini,1 B. Caccianiga,1 L. Cadonati,5 F. Calaprice,6 C. Carraro,7 P. Cavalcante,4 A. Chavarria,6 D. D’Angelo,1 S. Davini,7 A. Derbin,8 A. Etenko,9, 4 K. Fomenko,10, 4 D. Franco,11 C. Galbiati,6 S. Gazzana,4 C. Ghiano,4 M. Giammarchi,1 M. Goeger-Neff,12 A. Goretti,6 L. Grandi,6 E. Guardincerri,7 S. Hardy,13 Aldo Ianni,4 Andrea Ianni,6 V. Kobychev,14 D. Korablev,10 G. Korga,4 Y. Koshio,4 D. Kryn,11 M. Laubenstein,4 T. Lewke,12 E. Litvinovich,9 B. Loer,6 F. Lombardi,4 P. Lombardi,1 L. Ludhova,1 I. Machulin,9 S. Manecki,13 W. Maneschg,15 G. Manuzio,7 Q. Meindl,12 E. Meroni,1 L. Miramonti,1 M. Misiaszek,16, 4 D. Montanari,4, 6 P. Mosteiro,6 V. Muratova,8 L. Oberauer,12 M. Obolensky,11 F. Ortica,17 M. Pallavicini,7 L. Papp,4 C. Pe˜ na-Garay,18 L. Perasso,1 7 5 13 1 4 1 S. Perasso, A. Pocar, R.S. Raghavan, G. Ranucci, A. Razeto, A. Re, A. Romani,17 A. Sabelnikov,9 R. Saldanha,6 C. Salvo,7 S. Sch¨ onert,12 H. Simgen,15 M. Skorokhvatov,9 O. Smirnov,10 A. Sotnikov,10 S. Sukhotin,9 Y. Suvorov,4 R. Tartaglia,4 G. Testera,7 D. Vignaud,11 R.B. Vogelaar,13 F. von Feilitzsch,12 J. Winter,12 M. Wojcik,16 A. Wright,6 M. Wurm,12 J. Xu,6 O. Zaimidoroga,10 S. Zavatarelli,7 and G. Zuzel15 (Borexino Collaboration) 1 Dipartimento di Fisica, Universit` a degli Studi e INFN, 20133 Milano, Italy Chemical Engineering Department, Princeton University, Princeton, NJ 08544, USA 3 Institut f¨ ur Experimentalphysik, Universit¨ at, 22761 Hamburg, Germany 4 INFN Laboratori Nazionali del Gran Sasso, SS 17 bis Km 18+910, 67010 Assergi (AQ), Italy 5 Physics Department, University of Massachusetts, Amherst, MA 01003, USA 6 Physics Department, Princeton University, Princeton, NJ 08544, USA 7 Dipartimento di Fisica, Universit` a e INFN, Genova 16146, Italy 8 St. Petersburg Nuclear Physics Institute, 188350 Gatchina, Russia 9 NRC Kurchatov Institute, 123182 Moscow, Russia 10 Joint Institute for Nuclear Research, 141980 Dubna, Russia 11 Laboratoire AstroParticule et Cosmologie, 75231 Paris cedex 13, France 12 Physik Department, Technische Universit¨ at Muenchen, 85747 Garching, Germany 13 Physics Department, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA 14 Kiev Institute for Nuclear Research, 06380 Kiev, Ukraine 15 Max-Planck-Institut f¨ ur Kernphysik, 69029 Heidelberg, Germany 16 M. Smoluchowski Institute of Physics, Jagiellonian University, 30059 Krakow, Poland 17 Dipartimento di Chimica, Universit` a e INFN, 06123 Perugia, Italy 18 Instituto de F`ısica Corpuscular, CSIC-UVEG, Valencia 46071, Spain (Dated: August 25, 2011) 2

The rate of neutrino-electron elastic scattering interactions from 862 keV 7 Be solar neutrinos in Borexino is determined to be 46.0±1.5(stat)+1.5 This corre−1.6 (syst) counts/(day·100 ton). sponds to a νe -equivalent 7 Be solar neutrino flux of (3.10±0.15)×109 cm−2 s−1 and, under the assumption of νe transition to other active neutrino flavours, yields an electron neutrino survival probability of 0.51±0.07 at 862 keV. The no flavor change hypothesis is ruled out at 5.0 σ. 10 A global solar neutrino analysis with free fluxes determines Φpp =6.06+0.02 cm−2 s−1 and −0.06 ×10 9 −2 −1 ΦCN O