Low-energy-threshold analysis of the Phase I and Phase II data sets of the Sudbury Neutrino Observatory
B. AharmimDepartment of Physics and Astronomy, Laurentian University, Sudbury, Ontario P3E 2C6, CanadaS. N. AhmedDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaA. E. AnthonyDepartment of Physics, University of Texas at Austin, Austin, Texas 78712-0264, USAN. BarrosLaboratório de Instrumentação e Física Experimental de Partículas, Av. Elias Garcia 14, 1°, Lisboa, PortugalE. W. BeierDepartment of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USAA. BelleriveOttawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6, CanadaB. BeltránDepartment of Physics, University of Alberta, Edmonton, Alberta T6G 2R3, CanadaM. BergevinInstitute for Nuclear and Particle Astrophysics and Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USAS. D. BillerDepartment of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United KingdomK. BoudjemlineOttawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6, CanadaM. G. BoulayDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaT. H. BurrittCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAB. CaiDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaY-D. ChanInstitute for Nuclear and Particle Astrophysics and Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USAD. ChauhanDepartment of Physics and Astronomy, Laurentian University, Sudbury, Ontario P3E 2C6, CanadaM. ChenDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaB. T. ClevelandDepartment of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United KingdomG. A. CoxCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAX. DaiDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaHuiqiu DengDepartment of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USAJ. A. DetwilerInstitute for Nuclear and Particle Astrophysics and Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USAM. DiMarcoDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaP. J. DoeCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAG. DoucasDepartment of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United KingdomP.‐L. DrouinOttawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6, CanadaC. A. DubaCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAF. A. DuncanDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaM. DunfordDepartment of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USAE. D. EarleDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaS. R. ElliottCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAH. C. EvansDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaG. T. EwanDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaJ. FarineDepartment of Physics and Astronomy, Laurentian University, Sudbury, Ontario P3E 2C6, CanadaH. FerganiDepartment of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United KingdomF. FleurotDepartment of Physics and Astronomy, Laurentian University, Sudbury, Ontario P3E 2C6, CanadaR. J. FordDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaJ. A. FormaggioCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAN. GagnonCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAJ. TM. GoonDepartment of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana, USAK. GrahamDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaE. GuillianDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaS. HabibDepartment of Physics, University of Alberta, Edmonton, Alberta T6G 2R3, CanadaR. L. HahnChemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USAA. L. HallinDepartment of Physics, University of Alberta, Edmonton, Alberta T6G 2R3, CanadaE. D. HallmanDepartment of Physics and Astronomy, Laurentian University, Sudbury, Ontario P3E 2C6, CanadaPaul J. HarveyDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaR. HazamaCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAW. J. HeintzelmanDepartment of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USAJ. HeiseDepartment of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, CanadaR. L. HelmerTRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, CanadaA. HimeLos Alamos National Laboratory, Los Alamos, New Mexico 87545, USAChristian HowardDepartment of Physics, University of Alberta, Edmonton, Alberta T6G 2R3, CanadaM. A. HoweCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAM. HuangDepartment of Physics and Astronomy, Laurentian University, Sudbury, Ontario P3E 2C6, CanadaB. JamiesonDepartment of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, CanadaN. A. JelleyDepartment of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United KingdomK. KeeterSNOLAB, Sudbury, Ontario P3Y 1M3, CanadaJ. R. KleinDepartment of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USAL. L. KormosDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaM. KosDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaC. KrausDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaC. B. KraussDepartment of Physics, University of Alberta, Edmonton, Alberta T6G 2R3, CanadaT. KutterDepartment of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana, USAChristopher C. M. KybaDepartment of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USAJ. LawPhysics Department, University of Guelph, Guelph, Ontario N1G 2W1, CanadaI. LawsonPhysics Department, University of Guelph, Guelph, Ontario N1G 2W1, CanadaK. T. LeskoInstitute for Nuclear and Particle Astrophysics and Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USAJ. R. LeslieDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaI. LevineOttawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6, CanadaJ. C. LoachDepartment of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United KingdomR. MacLellanDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaS. MajerusDepartment of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United KingdomH.‐B. MakDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaJ. ManeiraLaboratório de Instrumentação e Física Experimental de Partículas, Av. Elias Garcia 14, 1°, Lisboa, PortugalR. D. MartínDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaN. McCauleyDepartment of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USAA.B. McDonaldDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaS. McGeeCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAM. L. MillerLaboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USAB. MonrealLaboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USAJ. MonroeLaboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USAB. MorissetteSNOLAB, Sudbury, Ontario P3Y 1M3, CanadaB. G. NickelPhysics Department, University of Guelph, Guelph, Ontario N1G 2W1, CanadaA. J. NobleDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaH. M. O’KeeffeDepartment of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United KingdomN. S. OblathCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAG. D. Orebi GannDepartment of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USAS. M. OserDepartment of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, CanadaRichard A. OttLaboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, USAS. J. M. PeetersDepartment of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, United KingdomA. W. P. PoonInstitute for Nuclear and Particle Astrophysics and Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USAG. PriorInstitute for Nuclear and Particle Astrophysics and Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USAS. D. ReitznerPhysics Department, University of Guelph, Guelph, Ontario N1G 2W1, CanadaK. RielageCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAB.C. RobertsonDepartment of Physics, Queen’s University, Kingston, Ontario K7L 3N6, CanadaR. G. H. RobertsonCenter for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USAM. H. SchwendenerDepartment of Physics and Astronomy, Laurentian University, Sudbury, Ontario P3E 2C6, CanadaJ. A. SecrestDepartment of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6396, USAS. R. SeibertDepartment of Physics, University of Texas at Austin, Austin, Texas 78712-0264, USAO. SimardOttawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6, Canada
2010en
ABI
Abstract
Results are reported from a joint analysis of Phase I and Phase II data from the Sudbury Neutrino Observatory. The effective electron kinetic energy threshold used is ${T}_{\mathrm{eff}}=3.5$ MeV, the lowest analysis threshold yet achieved with water Cherenkov detector data. In units of ${10}^{6}$ cm${}^{\ensuremath{-}2}$ ${\mathrm{s}}^{\ensuremath{-}1}$, the total flux of active-flavor neutrinos from $^{8}\mathrm{B}$ decay in the Sun measured using the neutral current (NC) reaction of neutrinos on deuterons, with no constraint on the $^{8}\mathrm{B}$ neutrino energy spectrum, is found to be ${\ensuremath{\Phi}}_{\mathrm{NC}}=5.{140}_{\ensuremath{-}0.158}^{+0.160}{\text{(stat)}}_{\ensuremath{-}0.117}^{+0.132}\text{(syst)}.$ These uncertainties are more than a factor of 2 smaller than previously published results. Also presented are the spectra of recoil electrons from the charged current reaction of neutrinos on deuterons and the elastic scattering of electrons. A fit to the Sudbury Neutrino Observatory data in which the free parameters directly describe the total $^{8}\mathrm{B}$ neutrino flux and the energy-dependent ${\ensuremath{\nu}}_{e}$ survival probability provides a measure of the total $^{8}\mathrm{B}$ neutrino flux ${\ensuremath{\Phi}}_{{}^{8}\mathrm{B}}=5.{046}_{\ensuremath{-}0.152}^{+0.159}{\text{(stat)}}_{\ensuremath{-}0.123}^{+0.107}\text{(syst)}$. Combining these new results with results of all other solar experiments and the KamLAND reactor experiment yields best-fit values of the mixing parameters of ${\ensuremath{\theta}}_{12}=34.{06}_{\ensuremath{-}0.84}^{+1.16}$ degrees and $\ensuremath{\Delta}{m}_{21}^{2}=7.{59}_{\ensuremath{-}0.21}^{+0.20}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ eV${}^{2}$. The global value of ${\ensuremath{\Phi}}_{{}^{8}\mathrm{B}}$ is extracted to a precision of ${}_{\ensuremath{-}2.95}^{+2.38}%$. In a three-flavor analysis the best fit value of $\mathrm{sin}{}^{2}{\ensuremath{\theta}}_{13}$ is $2.{00}_{\ensuremath{-}1.63}^{+2.09}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$. This implies an upper bound of $\mathrm{sin}{}^{2}{\ensuremath{\theta}}_{13}<0.057$ ($95%$ C.L.).
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