Low-energy-threshold analysis of the Phase I and Phase II data sets of the Sudbury Neutrino Observatory

Aharmim, B. and Ahmed, S. N. and Anthony, A. E. and Barros, N. and Beier, E. W. and Bellerive, A. and Beltran, B. and Bergevin, M. and Biller, S. D. and Boudjemline, K. and Boulay, M. G. and Burritt, T. H. and Cai, B. and Chan, Y. D. and Chauhan, D. and Chen, M. and Cleveland, B. T. and Cox, G. A. and Dai, X. and Deng, H. and Detwiler, J. and DiMarco, M. and Doe, P. J. and Doucas, G. and Drouin, P-L. and Duba, C. A. and Duncan, F. A. and Dunford, M. and Earle, E. D. and Elliott, S. R. and Evans, H. C. and Ewan, G. T. and Farine, J. and Fergani, H. and Fleurot, F. and Ford, R. J. and Formaggio, J. A. and Gagnon, N. and Goon, J. Tm and Graham, K. and Guillian, E. and Habib, S. and Hahn, R. L. and Hallin, A. L. and Hallman, E. D. and Harvey, P. J. and Hazama, R. and Heintzelman, W. J. and O'Keeffe, Helen and , SNO Collaboration and Kormos, Laura (2010) Low-energy-threshold analysis of the Phase I and Phase II data sets of the Sudbury Neutrino Observatory. Physical Review C, 81 (5). -. ISSN 0556-2813

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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-eff = 3.5MeV, the lowest analysis threshold yet achieved with water Cherenkov detector data. In units of 106 cm(-2) s(-1), the total flux of active-flavor neutrinos from B-8 decay in the Sun measured using the neutral current (NC) reaction of neutrinos on deuterons, with no constraint on the B-8 neutrino energy spectrum, is found to be Phi(NC) = 5.140(-0.158)(+0.160)(stat)(-0.117)(+0.132)(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 B-8 neutrino flux and the energy-dependent nu(e) survival probability provides a measure of the total B-8 neutrino flux Phi(8B) = 5.046(-0.152)(+0.159)(stat)(-0.123)(+0.107)(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 theta(12) = 34.06(-0.84)(+1.16) degrees and Delta m(21)(2) = 7.59(-0.21)(+0.20) x 10(-5) eV(2). The global value of Phi(8B) is extracted to a precision of (+2.38)(-2.95)%. In a three-flavor analysis the best fit value of sin(2) theta(13) is 2.00(-1.63)(+2.09) x 10(-2). This implies an upper bound of sin(2) theta(13) < 0.057 (95% C.L.).

Item Type:
Journal Article
Journal or Publication Title:
Physical Review C
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© 2010 The American Physical Society
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Deposited On:
23 Jan 2012 08:59
Last Modified:
11 Jul 2020 04:03