D. Besson, S. Anderson, V. V. Frolov, D. T. Gong, Y. Kubota, S. Z. Li, R. Poling, A. Smith, C. J. Stepaniak, J. Urheim, Z. Metreveli, K. K. Seth, A. Tomaradze, P. Zweber, K. Arms, E. Eckhart, K. K. Gan, C. Gwon, T. K. Pedlar, E. von Toerne, H. Severini, P. Skubic, S. A. Dytman, J. A. Mueller, S. Nam, V. Savinov, J. W. Hinson, G. S. Huang, J. Lee, D. H. Miller, V. Pavlunin, B. Sanghi, E. I. Shibata, I. P. J. Shipsey, D. Cronin-Hennessy, C. S. Park, W. Park, J. B. Thayer, E. H. Thorndike, T. E. Coan, Y. S. Gao, F. Liu, R. Stroynowski, M. Artuso, C. Boulahouache, S. Blusk, E. Dambasuren, O. Dorjkhaidav, R. Mountain, H. Muramatsu, R. Nandakumar, T. Skwarnicki, S. Stone, J. C. Wang, A. H. Mahmood, S. E. Csorna, I. Danko, G. Bonvicini, D. Cinabro, M. Dubrovin, S. McGee, A. Bornheim, E. Lipeles, S. P. Pappas, A. Shapiro, W. M. Sun, A. J. Weinstein, R. A. Briere, G. P. Chen, T. Ferguson, G. Tatishvili, H. Vogel, M. E. Watkins, N. E. Adam, J. P. Alexander, K. Berkelman, V. Boisvert, D. G. Cassel, J. E. Duboscq, K. M. Ecklund, R. Ehrlich, R. S. Galik, L. Gibbons, B. Gittelman, S. W. Gray, D. L. Hartill, B. K. Heltsley, L. Hsu, C. D. Jones, J. Kandaswamy, D. L. Kreinick, A. Magerkurth, H. Mahlke-Kruger, T. O. Meyer, N. B. Mistry, J. R. Patterson, D. Peterson, J. Pivarski, S. J. Richichi, D. Riley, A. J. Sadoff, H. Schwarthoff, M. R. Shepherd, J. G. Thayer, D. Urner, T. Wilksen, A. Warburton, M. Weinberger, S. B. Athar, P. Avery, L. Breva-Newell, V. Potlia, H. Stoeck, J. Yelton, B. I. Eisenstein, G. D. Gollin, I. Karliner, N. Lowrey, C. Plager, C. Sedlack, M. Selen, J. J. Thaler, J. Williams, and K. W. Edwards
The third phase of the Sudbury Neutrino Observatory (SNO) experiment added an array of 3He proportional counters to the detector. The purpose of this neutral-current detection (NCD) array was to observe neutrons resulting from neutral-current solar-neutrino–deuteron interactions. We have developed a detailed simulation of current pulses from NCD array proportional counters, from the primary neutron capture on 3He through NCD array signal-processing electronics. This NCD array MC simulation was used to model the alpha-decay background in SNO's third-phase 8B solar-neutrino measurement.
S.N. Ahmed, 10 A.E. Anthony,14 E.W. Beier, 9 A. Bellerive,3 S.D. Biller,8 J. Boger, 2 M.G. Boulay,7 M.G. Bowler,8 T.J. Bowles, 7 S.J. Brice, 7 T.V. Bullard,13 Y.D. Chan, 6 M. Chen,10 X. Chen,6 B.T. Cleveland, 8 G.A. Cox,13 X. Dai,3, 8 F. Dalnoki-Veress, 3 P.J. Doe, 13 R.S. Dosanjh, 3 G. Doucas, 8 M.R. Dragowsky, 7 C.A. Duba, 13 F.A. Duncan, 10 M. Dunford,9 J.A. Dunmore, 8 E.D. Earle, 10 S.R. Elliott,7 H.C. Evans, 10 G.T. Ewan, 10 J. Farine, 5,3 H. Fergani, 8 F. Fleurot, 5 J.A. Formaggio, 13
Since November 25th, 2004, the Sudbury Neutrino Observatory has been taking production data in its third and final phase. For this phase a 'Neutral-Current Detection (NCD) Array', consisting of 36 strings of He-3 proportional counters and 4 strings of He-4 proportional counters, was deployed in SNO's D2O volume. It supplements the Cherenkov detector, consisting of 9456 photomultiplier tubes, present in the previous two phases by offering an independent measurement. of the solar neutral current rate. The He-3 counters detect neutrons from neutrino-deuteron neutral current interactions in the D2O. We describe the calibration of this array.
We have performed three searches for high-frequency signals in the solar neutrino flux measured by the Sudbury Neutrino Observatory (SNO), motivated by the possibility that solar g-mode oscillations could affect the production or propagation of solar B neutrinos. The first search looked for any significant peak in the frequency range 1/day to 144/day, with a sensitivity to sinusoidal signals with amplitudes of 12% or greater. The second search focused on regions in which g-mode signals have been claimed by experiments aboard the SoHO satellite, and was sensitive to signals with amplitudes of 10% or greater. The third search looked for extra power across the entire frequency band. No statistically significant signal was detected in any of the three searches.
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 Teff=3.5 MeV, 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 8B decay in the Sun measured using the neutral current (NC) reaction of neutrinos on deuterons, with no constraint on the 8B neutrino energy spectrum, is found to be FNC=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 8B neutrino flux and the energy-dependent e survival probability provides a measure of the total 8B neutrino flux F8B=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 12=34.06-0.84+1.16 degrees and m212=7.59-0.21+0.2010-5 eV2. The global value of 8B is extracted to a precision of -2.95+2.38%. In a three-flavor analysis the best fit value of sin213 is 2.00-1.63+2.0910-2. This implies an upper bound of sin213<0.057 (95% C.L.).
We report a measurement of the exclusive B+ meson decay to the D-s(()*K-)(+)pi(+) final state using 657 x 10(6) B (B) over bar pairs collected at the gamma(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We use D-s* -> D-s(-) -> phi pi(-), (K) over bar*(892)K-0(-) and (KSK-)-K-0 decay modes for D-s(()*()) reconstruction and measure the following branching fractions: B(B+ -> Ds-K+pi(+)) = (1.71(-0.07)(+0.08)(stat)(-0.20)(+0.20)(syst) +/- 0.15(B-int)) x 10(-4) and B(B+ -> D-s*K--(+)pi(+)) = (1.31(-0.12)(+0.13)(stat)(-0.25)(+0.25)(syst) +/- 0.12(B-int)) x 10(-4). The uncertainties are due to statistics, experimental systematic errors, and uncertainties of intermediate branching fractions, respectively.
The Sudbury Neutrino Observatory (SNO) used an array of 3He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active (nu_x) 8B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5.54_-0.31;+0.33(stat)-0.34+0.36(syst)x10(6) cm(-2) s(-1), in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields Deltam2=7.59_-0.21;+0.19x10(-5) eV2 and theta=34.4_-1.2;+1.3 degrees. The uncertainty on the mixing angle has been reduced from SNO's previous results.
We describe a measurement of B−B0 mixing parameters exploiting a method of partial reconstruction of the decay chains B → Dπ and B → Dρ. Using 9.6 ×10BB pairs collected at the Cornell Electron Storage Ring, we find χd = 0.198 ± 0.013 ± 0.014, |yd| < 0.41 at 95% confidence level, and |Re(ǫB)| < 0.034 at 95% confidence level.
The Sudbury Neutrino Observatory (SNO) used an array of 3 He proportional counters to measure the rate of neutral-current interactions in heavy water and precisely determined the total active ( ν x ) 8 B solar neutrino flux. This technique is independent of previous methods employed by SNO. The total flux is found to be 5 . 54 + 0 . 33 − 0 . 31 (stat) + 0 . 36 − 0 . 34 (syst) × 10 6 cm − 2 s − 1 , in agreement with previous measurements and standard solar models. A global analysis of solar and reactor neutrino results yields ∆ m 2 = 7 . 94 + 0 . 42 − 0 . 26 × 10 − 5 eV 2 and θ = 33 . 8 + 1 . 4 − 1 3 degrees. The uncertainty on the mixing angle has been reduced from SNO’s previous results.
This article provides the complete description of results from the Phase I data set of the Sudbury Neutrino Observatory (SNO). The Phase I data set is based on a 0.65 kt-year exposure of heavy water to the solar 8B neutrino flux. Included here are details of the SNO physics and detector model, evaluations of systematic uncertainties, and estimates of backgrounds. Also discussed are SNO's approach to statistical extraction of the signals from the three neutrino reactions (charged current, neutral current, and elastic scattering) and the results of a search for a day-night asymmetry in the ?e flux. Under the assumption that the 8B spectrum is undistorted, the measurements from this phase yield a solar ?e flux of ?(?e) = 1.76+0.05?0.05(stat.)+0.09?0.09 (syst.) x 106 cm?2 s?1, and a non-?e component ?(? mu) = 3.41+0.45?0.45(stat.)+0.48?0.45 (syst.) x 106 cm?2 s?1. The sum of these components provides a total flux in excellent agreement with the predictions of Standard Solar Models. The day-night asymmetry in the ?e flux is found to be Ae = 7.0 +- 4.9 (stat.)+1.3?1.2 percent (sys.), when the asymmetry in the total flux is constrained to be zero.
An array of Neutral-Current Detectors (NCDs) has been built in order to make a unique measurement of the total active flux of solar neutrinos in the Sudbury Neutrino Observatory (SNO). Data in the third phase of the SNO experiment were collected between November 2004 and 2006, after the NCD array was added to improve the neutral-current sensitivity of the SNO detector. This array consisted of 36 strings of proportional counters filled with a mixture of 3He and CF4 gas capable of detecting the neutrons liberated by the neutrino-deuteron neutral-current reaction in the D2O, and four strings filled with a mixture of 4He and CF4 gas for background measurements. The proportional counter diameter is 5cm. The total deployed array length was 398m. The SNO NCD array is the lowest-radioactivity large array of proportional counters ever produced. This article describes the design, construction, deployment, and characterization of the NCD array, discusses the electronics and data acquisition system, and considers event signatures and backgrounds.
An array of Neutral-Current Detectors (NCDs) has been built in order to make a unique measurement of the total active
A search has been made for neutrinos from the hep reaction in the Sun and from the diffuse supernova neutrino background (DSNB) using data collected during the first operational phase of the Sudbury Neutrino Observatory, with an exposure of 0.65 ktons yr. For the hep neutrino search, two events are observed in the effective electron energy range of 14: 3 MeV < T-eff < 20 MeV, where 3.1 background events are expected. After accounting for neutrino oscillations, an upper limit of 2.3 x 10(4) cm(-2) s(-1) at the 90% confidence level is inferred on the integral total flux of hep neutrinos. For DSNB neutrinos, no events are observed in the effective electron energy range of 21 MeV < T-eff < 35 MeV, and, consequently, an upper limit on the v(e) component of the DSNB flux in the neutrino energy range of 22.9 MeV < E-v < 36.9 MeV of 70 cm(-2) s(-1) is inferred at the 90% confidence level. This is an improvement by a factor of 6.5 on the previous best upper limit on the hep neutrino flux and by 2 orders of magnitude on the previous upper limit on the v(e) component of the DSNB flux.
A search has been made for sinusoidal periodic variations in the $^8$B solar neutrino flux using data collected by the Sudbury Neutrino Observatory over a 4-year time interval. The variation at a period of one year is consistent with modulation of the $^8$B neutrino flux by the Earth's orbital eccentricity. No significant sinusoidal periodicities are found with periods between 1 day and 10 years with either an unbinned maximum likelihood analysis or a Lomb-Scargle periodogram analysis. The data are inconsistent with the hypothesis that the results of the recent analysis by Sturrock et al., based on elastic scattering events in Super-Kamiokande, can be attributed to a 7% sinusoidal modulation of the total $^8$B neutrino flux.