Browsing by Author "Hofmann, M."

Now showing 1 - 8 of 8
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    Characterization of the spontaneous light emission of the PMTs used in the Double Chooz experiment
    Abe, Y.; Abrahao, T.; Almazan, H.; Alt, C.; Appel, S.; Baussan, E.; Bekman, I.; Bergevin, M.; Bezerra, T. J. C.; Bezrukhov, Leonid B.; Blucher, E.; Brugiere, T.; Buck, C.; Busenitz, J.; Cabrera, A.; Calvo, E.; Camilleri, Leslie; Carr, Rachel E.; Cerrada, M.; Chauveau, E.; Chimenti, P.; Collin, A. P.; Conover, E.; Conrad, Janet M.; Crespo-Anadon, J. I.; Crum, K.; Cucoanes, A. S.; Damon, E.; Dawson, J. V.; de Kerret, H.; Dhooghe, J.; Dietrich, D.; Djurcic, Zelimir; dos Anjos, J. C.; Dracos, M.; Etenko, A.; Fallot, M.; Felde, J.; Fernandes, S. M.; Fischer, V.; Franco, D.; Franke, M.; Furuta, H.; Gil-Botella, I.; Giot, L.; Goger-Neff, M.; Gomez, H.; Gonzalez, L. F. G.; Goodenough, L.; Goodman, M. C.; Haag, N.; Hara, T.; Haser, J.; Hellwig, D.; Hofmann, M.; Horton-Smith, Glenn A.; Hourlier, A.; Ishitsuka, M.; Jiménez, S.; Jochum, J.; Jollet, C.; Kaether, F.; Kalousis, L. N.; Kamyshkov, Y.; Kaneda, M.; Kaplan, D. M.; Kawasaki, T.; Kemp, E.; Kryn, D.; Kuze, M.; Lachenmaier, Tobias; Lane, C. E.; Lasserre, T.; Letourneau, A.; Lhuillier, D.; Lima, H. P.; Lindner, M.; Lopez-Castano, J. M.; LoSecco, J. M.; Lubsandorzhiev, B. K.; Lucht, S.; Maeda, J.; Mariani, Camillo; Maricic, Jelena; Martino, J.; Matsubara, T.; Mention, G.; Meregaglia, A.; Miletic, T.; Milincic, R.; Minotti, A.; Nagasaka, Y.; Navas-Nicolás, D.; Novella, P.; Nunokawa, H.; Oberauer, L.; Obolensky, M.; Onillon, A.; Osborn, A.; Palomares, C.; Pepe, I. M.; Perasso, S.; Porta, A.; Pronost, G.; Reichenbacher, J.; Reinhold, B.; Roehling, M.; Roncin, R.; Rybolt, B.; Sakamoto, Y.; Santorelli, R.; Schilithz, A. C.; Schoenert, S.; Schoppmann, S.; Shaevitz, Marjorie Hansen; Sharankova, R.; Shrestha, D.; Sibille, V.; Sinev, V.; Skorokhvatov, Mikhail D.; Smith, E.; Soiron, M.; Spitz, Joshua; Stahl, A.; Stancu, Ion; Stokes, Lee F. F.; Strait, M.; Suekane, F.; Sukhotin, S.; Sumiyoshi, T.; Sun, Y.; Svoboda, R.; Terao, K.; Tonazzo, A.; Thi, H. H. T.; Valdiviesso, G. A.; Vassilopoulos, N.; Verdugo, A.; Veyssiere, C.; Vivier, M.; von Feilitzsch, F.; Wagner, S.; Walsh, N.; Watanabe, H.; Wiebusch, C.; Wurm, M.; Yang, G.; Yermia, F.; Zimmer, V. (IOP, 2016-08-01)
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    Demonstration Of A Cylindrically Symmetric Second-Order Nonlinear Fiber with Self-Assembled Organic Surface Layers
    Daengngam, Chalongrat; Hofmann, M.; Liu, Z. W.; Wang, Anbo; Heflin, James R.; Xu, Yong (Optical Society of America, 2011-05-01)
    We report the fabrication and characterization of a cylindrically symmetric fiber structure that possesses significant and thermodynamically stable second-order nonlinearity. Such fiber structure is produced through nanoscale self-assembly of nonlinear molecules on a silica fiber taper and possesses full rotational symmetry. Despite its highly symmetric configuration, we observed significant second harmonic generation (SHG) and obtained good agreement between experimental results and theoretical predictions. (C) 2011 Optical Society of America
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    Direct measurement of backgrounds using reactor-off data in Double Chooz
    Abe, Y.; Aberle, C.; dos Anjos, J. C.; Barriere, J. C.; Bergevin, M.; Bernstein, A.; Bezerra, T. J. C.; Bezrukhov, Leonid B.; Blucher, E.; Bowden, N. S.; Buck, C.; Busenitz, J.; Cabrera, A.; Caden, E.; Camilleri, Leslie; Carr, Rachel E.; Cerrada, M.; Chang, P. J.; Chimenti, P.; Classen, T.; Collin, A. P.; Conover, E.; Conrad, Janet M.; Crespo-Anadon, J. I.; Crum, K.; Cucoanes, A. S.; D'Agostino, M. V.; Damon, E.; Dawson, J. V.; Dazeley, S.; Dietrich, D.; Djurcic, Zelimir; Dracos, M.; Durand, V.; Ebert, J.; Efremenko, Y.; Elnimr, M.; Erickson, A.; Etenko, A.; Fallot, M.; Fechner, M.; von Feilitzsch, F.; Felde, J.; Fernandes, S. M.; Fischer, V.; Franco, D.; Franke, A. J.; Franke, M.; Furuta, H.; Gama, R.; Gil-Botella, I.; Giot, L.; Goger-Neff, M.; Gonzalez, L. F. G.; Goodenough, L.; Goodman, M. C.; Goon, J. T. M.; Greiner, D.; Haag, N.; Habib, S.; Hagner, C.; Hara, T.; Hartmann, F. X.; Haser, J.; Hatzikoutelis, A.; Hayakawa, T.; Hofmann, M.; Horton-Smith, Glenn A.; Hourlier, A.; Ishitsuka, M.; Jochum, J.; Jollet, C.; Jones, C. L.; Kaether, F.; Kalousis, L. N.; Kamyshkov, Y.; Kaplan, D. M.; Kawasaki, T.; Keefer, G.; Kemp, E.; de Kerret, H.; Kibe, Y.; Konno, T.; Kryn, D.; Kuze, M.; Lachenmaier, Tobias; Lane, C. E.; Langbrandtner, C.; Lasserre, T.; Letourneau, A.; Lhuillier, D.; Lima, H. P.; Lindner, M.; Lopez-Castano, J. M.; LoSecco, J. M.; Lubsandorzhiev, B. K.; Lucht, S.; McKee, D.; Maeda, J.; Maesano, C. N.; Mariani, Camillo; Maricic, Jelena; Martino, J.; Matsubara, T.; Mention, G.; Meregaglia, A.; Meyer, M.; Miletic, T.; Milincic, R.; Miyata, H.; Mueller, T. A.; Nagasaka, Y.; Nakajima, K.; Novella, P.; Obolensky, M.; Oberauer, L.; Onillon, A.; Osborn, A.; Ostrovskiy, I.; Palomares, C.; Pepe, I. M.; Perasso, S.; Perrin, P.; Pfahler, P.; Porta, A.; Potzel, W.; Pronost, G.; Reichenbacher, J.; Reinhold, B.; Remoto, A.; Roehling, M.; Roncin, R.; Roth, S.; Rybolt, B.; Sakamoto, Y.; Santorelli, R.; Sato, F.; Schoenert, S.; Schoppmann, S.; Schwetz, T.; Shaevitz, Marjorie Hansen; Shimojima, S.; Shrestha, D.; Sida, J. L.; Sinev, V.; Skorokhvatov, Mikhail D.; Smith, E.; Spitz, Joshua; Stahl, A.; Stancu, Ion; Stokes, Lee F. F.; Strait, M.; Stuken, A.; Suekane, F.; Sukhotin, S.; Sumiyoshi, T.; Sun, Y.; Svoboda, R.; Terao, K.; Tonazzo, A.; Toups, M.; Thi, H. H. T.; Valdiviesso, G. A.; Veyssiere, C.; Wagner, S.; Watanabe, H.; White, B.; Wiebusch, C.; Winslow, L.; Worcester, M.; Wurm, M.; Yermia, F.; Zimmer, V.; Double Chooz, Collaboration (American Physical Society, 2013-01-08)
    Double Chooz is unique among modern reactor-based neutrino experiments studying (nu) over bar (e) disappearance in that data can be collected with all reactors off. In this paper, we present data from 7.53 days of reactor-off running. Applying the same selection criteria as used in the Double Chooz reactor-on oscillation analysis, a measured background rate of 1.0 +/- 0.4 events/day is obtained. The background model for accidentals, cosmogenic beta-n-emitting isotopes, fast neutrons from cosmic muons, and stopped-mu decays used in the oscillation analysis is demonstrated to be correct within the uncertainties. Kinematic distributions of the events, which are dominantly cosmic-ray-produced correlated-background events, are provided. The background rates are scaled to the shielding depths of two other reactor-based oscillation experiments, Daya Bay and RENO.
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    First test of Lorentz violation with a reactor-based antineutrino experiment
    Abe, Y.; Aberle, C.; dos Anjos, J. C.; Bergevin, M.; Bernstein, A.; Bezerra, T. J. C.; Bezrukhov, Leonid B.; Blucher, E.; Bowden, N. S.; Buck, C.; Busenitz, J.; Cabrera, A.; Caden, E.; Camilleri, Leslie; Carr, Rachel E.; Cerrada, M.; Chang, P. J.; Chimenti, P.; Classen, T.; Collin, A. P.; Conover, E.; Conrad, Janet M.; Crespo-Anadon, J. I.; Crum, K.; Cucoanes, A. S.; D'Agostino, M. V.; Damon, E.; Dawson, J. V.; Dazeley, S.; Dietrich, D.; Djurcic, Zelimir; Dracos, M.; Durand, V.; Ebert, J.; Efremenko, Y.; Elnimr, M.; Erickson, A.; Fallot, M.; Fechner, M.; von Feilitzsch, F.; Felde, J.; Fischer, V.; Franco, D.; Franke, A. J.; Franke, M.; Furuta, H.; Gama, R.; Gil-Botella, I.; Giot, L.; Goger-Neff, M.; Gonzalez, L. F. G.; Goodman, M. C.; Goon, J. T.; Greiner, D.; Haag, N.; Habib, S.; Hagner, C.; Hara, T.; Hartmann, F. X.; Haser, J.; Hatzikoutelis, A.; Hayakawa, T.; Hofmann, M.; Horton-Smith, Glenn A.; Ishitsuka, M.; Jochum, J.; Jollet, C.; Jones, C. L.; Kaether, F.; Kalousis, L. N.; Kamyshkov, Y.; Kaplan, D. M.; Katori, T.; Kawasaki, T.; Keefer, G.; Kemp, E.; de Kerret, H.; Konno, T.; Kryn, D.; Kuze, M.; Lachenmaier, Tobias; Lane, C. E.; Lasserre, T.; Letourneau, A.; Lhuillier, D.; Lima, H. P.; Lindner, M.; Lopez-Castano, J. M.; LoSecco, J. M.; Lubsandorzhiev, B. K.; Lucht, S.; McKee, D.; Maeda, J.; Maesano, C. N.; Mariani, Camillo; Maricic, Jelena; Martino, J.; Matsubara, T.; Mention, G.; Meregaglia, A.; Meyer, M.; Miletic, T.; Milincic, R.; Miyata, H.; Mueller, T. A.; Nagasaka, Y.; Nakajima, K.; Novella, P.; Obolensky, M.; Oberauer, L.; Onillon, A.; Osborn, A.; Ostrovskiy, I.; Palomares, C.; Pepe, I. M.; Perasso, S.; Perrin, P.; Pfahler, P.; Porta, A.; Potzel, W.; Pronost, G.; Reichenbacher, J.; Reinhold, B.; Remoto, A.; Roehling, M.; Roncin, R.; Roth, S.; Rybolt, B.; Sakamoto, Y.; Santorelli, R.; Sato, F.; Schoenert, S.; Schoppmann, S.; Schwetz, T.; Shaevitz, Marjorie Hansen; Shrestha, D.; Sida, J. L.; Sinev, V.; Skorokhvatov, Mikhail D.; Smith, E.; Spitz, Joshua; Stahl, A.; Stancu, Ion; Stokes, Lee F. F.; Strait, M.; Stuken, A.; Suekane, F.; Sukhotin, S.; Sumiyoshi, T.; Sun, Y.; Terao, K.; Tonazzo, A.; Toups, M.; Thi, H. H. T.; Valdiviesso, G. A.; Veyssiere, C.; Wagner, S.; Watanabe, H.; White, B.; Wiebusch, C.; Winslow, L.; Worcester, M.; Wurm, M.; Yanovitch, E.; Yermia, F.; Zimmer, V.; Double Chooz, Collaboration (American Physical Society, 2012-12-28)
    We present a search for Lorentz violation with 8249 candidate electron antineutrino events taken by the Double Chooz experiment in 227.9 live days of running. This analysis, featuring a search for a sidereal time dependence of the events, is the first test of Lorentz invariance using a reactor-based antineutrino source. No sidereal variation is present in the data and the disappearance results are consistent with sidereal time independent oscillations. Under the Standard-Model Extension, we set the first limits on 14 Lorentz violating coefficients associated with transitions between electron and tau flavor, and set two competitive limits associated with transitions between electron and muon flavor.
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    Improved measurements of the neutrino mixing angle theta(13) with the Double Chooz detector
    Abe, Y.; dos Anjos, J. C.; Barriere, J. C.; Baussan, E.; Bekman, I.; Bergevin, M.; Bezerra, T. J. C.; Bezrukhov, Leonid B.; Blucher, E.; Buck, C.; Busenitz, J.; Cabrera, A.; Caden, E.; Camilleri, Leslie; Carr, Rachel E.; Cerrada, M.; Chang, P. J.; Chauveau, E.; Chimenti, P.; Collin, A. P.; Conover, E.; Conrad, Janet M.; Crespo-Anadon, J. I.; Crum, K.; Cucoanes, A. S.; Damon, E.; Dawson, J. V.; Dhooghe, J.; Dietrich, D.; Djurcic, Zelimir; Dracos, M.; Elnimr, M.; Etenko, A.; Fallot, M.; von Feilitzsch, F.; Felde, J.; Fernandes, S. M.; Fischer, V.; Franco, D.; Franke, M.; Furuta, H.; Gil-Botella, I.; Giot, L.; Goger-Neff, M.; Gonzalez, L. F. G.; Goodenough, L.; Goodman, M. C.; Grant, C.; Haag, N.; Hara, T.; Haser, J.; Hofmann, M.; Horton-Smith, Glenn A.; Hourlier, A.; Ishitsuka, M.; Jochum, J.; Jollet, C.; Kaether, F.; Kalousis, L. N.; Kamyshkov, Y.; Kaplan, D. M.; Kawasaki, T.; Kemp, E.; de Kerret, H.; Kryn, D.; Kuze, M.; Lachenmaier, Tobias; Lane, C. E.; Lasserre, T.; Letourneau, A.; Lhuillier, D.; Lima, H. P., Jr.; Lindner, M.; Lopez-Castano, J. M.; LoSecco, J. M.; Lubsandorzhiev, B. K.; Lucht, S.; Maeda, J.; Mariani, Camillo; Maricic, Jelena; Martino, J.; Matsubara, T.; Mention, G.; Meregaglia, A.; Miletic, T.; Milincic, R.; Minotti, A.; Nagasaka, Y.; Nikitenko, Y.; Novella, P.; Oberauer, L.; Obolensky, M.; Onillon, A.; Osborn, A.; Palomares, C.; Pepe, I. M.; Perasso, S.; Pfahler, P.; Porta, A.; Pronost, G.; Reichenbacher, J.; Reinhold, B.; Roehling, M.; Roncin, R.; Roth, S.; Rybolt, B.; Sakamoto, Y.; Santorelli, R.; Schilithz, A. C.; Schoenert, S.; Schoppmann, S.; Shaevitz, Marjorie Hansen; Sharankova, R.; Shimojima, S.; Shrestha, D.; Sibille, V.; Sinev, V.; Skorokhvatov, Mikhail D.; Smith, E.; Spitz, Joshua; Stahl, A.; Stancu, Ion; Stokes, Lee F. F.; Strait, M.; Stuken, A.; Suekane, F.; Sukhotin, S.; Sumiyoshi, T.; Sun, Y.; Svoboda, R.; Terao, K.; Tonazzo, A.; Thi, H. H. Trinh; Valdiviesso, G. A.; Vassilopoulos, N.; Veyssiere, C.; Vivier, M.; Wagner, S.; Walsh, N.; Watanabe, H.; Wiebusch, C.; Winslow, L.; Wurm, M.; Yang, G.; Yermia, F.; Zimmer, V. (Springer, 2014-10-14)
    The Double Chooz experiment presents improved measurements of the neutrino mixing angle theta(13) using the data collected in 467.90 live days from a detector positioned at an average distance of 1050m from two reactor cores at the Chooz nuclear power plant. Several novel techniques have been developed to achieve significant reductions of the backgrounds and systematic uncertainties with respect to previous publications, whereas the efficiency of the (nu) over bar (e) signal has increased. The value of theta(13) is measured to be sin(2)2 theta(13) = 0.090(-0.029)(+0.032) from a fit to the observed energy spectrum. Deviations from the reactor (nu) over bar (e) prediction observed above a prompt signal energy of 4 MeV and possible explanations are also reported. A consistent value of theta(13) is obtained from a fit to the observed rate as a function of the reactor power independently of the spectrum shape and background estimation, demonstrating the robustness of the theta(13) measurement despite the observed distortion.
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    Measurement of theta(13) in Double Chooz using neutron captures on hydrogen with novel background rejection techniques
    Abe, Y.; Appel, S.; Abrahao, T.; Almazan, H.; Alt, C.; dos Anjos, J. C.; Barriere, J. C.; Baussan, E.; Bekman, I.; Bergevin, M.; Bezerra, T. J. C.; Bezrukhov, Leonid B.; Blucher, E.; Brugiere, T.; Buck, C.; Busenitz, J.; Cabrera, A.; Camilleri, Leslie; Carr, Rachel E.; Cerrada, M.; Chauveau, E.; Chimenti, P.; Collin, A. P.; Conrad, Janet M.; Crespo-Anadon, J. I.; Crum, K.; Cucoanes, A. S.; Damon, E.; Dawson, J. V.; Dhooghe, J.; Dietrich, D.; Djurcic, Zelimir; Dracos, M.; Etenko, A.; Fallot, M.; von Feilitzsch, F.; Felde, J.; Fernandes, S. M.; Fischer, V.; Franco, D.; Franke, M.; Furuta, H.; Gil-Botella, I.; Giot, L.; Goger-Neff, M.; Gomez, H.; Gonzalez, L. F. G.; Goodenough, L.; Goodman, M. C.; Haag, N.; Hara, T.; Haser, J.; Hellwig, D.; Hofmann, M.; Horton-Smith, Glenn A.; Hourlier, A.; Ishitsuka, M.; Jochum, J.; Jollet, C.; Kaether, F.; Kalousis, L. N.; Kamyshkov, Y.; Kaneda, M.; Kaplan, D. M.; Kawasaki, T.; Kemp, E.; de Kerret, H.; Kryn, D.; Kuze, M.; Lachenmaier, Tobias; Lane, C. E.; Lasserre, T.; Letourneau, A.; Lhuillier, D.; Lima, H. P.; Lindner, M.; Lopez-Castano, J. M.; LoSecco, J. M.; Lubsandorzhiev, B. K.; Lucht, S.; Maeda, J.; Mariani, Camillo; Maricic, Jelena; Martino, J.; Matsubara, T.; Mention, G.; Meregaglia, A.; Miletic, T.; Milincic, R.; Minotti, A.; Nagasaka, Y.; Navas-Nicolás, D.; Novella, P.; Oberauer, L.; Obolensky, M.; Onillon, A.; Osborn, A.; Palomares, C.; Pepe, I. M.; Perasso, S.; Porta, A.; Pronost, G.; Reichenbacher, J.; Reinhold, B.; Roehling, M.; Roncin, R.; Rybolt, B.; Sakamoto, Y.; Santorelli, R.; Schilithz, A. C.; Schoenert, S.; Schoppmann, S.; Shaevitz, Marjorie Hansen; Sharankova, R.; Shrestha, D.; Sibille, V.; Sinev, V.; Skorokhvatov, Mikhail D.; Smith, E.; Soiron, M.; Spitz, Joshua; Stahl, A.; Stancu, Ion; Stokes, Lee F. F.; Strait, M.; Suekane, F.; Sukhotin, S.; Sumiyoshi, T.; Sun, Y.; Svoboda, R.; Terao, K.; Tonazzo, A.; Thi, H. H. T.; Valdiviesso, G. A.; Vassilopoulos, N.; Veyssiere, C.; Vivier, M.; Wagner, S.; Walsh, N.; Watanabe, H.; Wiebusch, C.; Wurm, M.; Yang, G.; Yermia, F.; Zimmer, V. (Springer, 2016-01-27)
    The Double Chooz collaboration presents a measurement of the neutrino mixing angle θ13 using reactor νe observed via the inverse beta decay reaction in which the neutron is captured on hydrogen. This measurement is based on 462.72 live days data, approximately twice as much data as in the previous such analysis, collected with a detector positioned at an average distance of 1050m from two reactor cores. Several novel techniques have been developed to achieve significant reductions of the backgrounds and systematic uncertainties. Accidental coincidences, the dominant background in this analysis, are suppressed by more than an order of magnitude with respect to our previous publication by a multi-variate analysis. These improvements demonstrate the capability of precise measurement of reactor νe without gadolinium loading. Spectral distortions from the νe reactor flux predictions previously reported with the neutron capture on gadolinium events are confirmed in the independent data sample presented here. A value of sin2 2θ13 = 0.095+0.038−0.039(stat+syst) is obtained from a fit to the observed event rate as a function of the reactor power, a method insensitive to the energy spectrum shape. A simultaneous fit of the hydrogen capture events and of the gadolinium capture events yields a measurement of sin2 2θ13 = 0.088 ± 0.033(stat+syst).
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    Ortho-positronium observation in the Double Chooz experiment
    Abe, Y.; dos Anjos, J. C.; Barriere, J. C.; Baussan, E.; Bekman, I.; Bergevin, M.; Bezerra, T. J. C.; Bezrukhov, Leonid B.; Blucher, E.; Buck, C.; Busenitz, J.; Cabrera, A.; Caden, E.; Camilleri, Leslie; Carr, Rachel E.; Cerrada, M.; Chang, P. J.; Chauveau, E.; Chimenti, P.; Collin, A. P.; Conover, E.; Conrad, Janet M.; Crespo-Anadon, J. I.; Crum, K.; Cucoanes, A. S.; Damon, E.; Dawson, J. V.; Dhooghe, J.; Dietrich, D.; Djurcic, Zelimir; Dracos, M.; Elnimr, M.; Etenko, A.; Fallot, M.; von Feilitzsch, F.; Felde, J.; Fernandes, S. M.; Fischer, V.; Franco, D.; Franke, M.; Furuta, H.; Gil-Botella, I.; Giot, L.; Goger-Neff, M.; Gonzalez, L. F. G.; Goodenough, L.; Goodman, M. C.; Grant, C.; Haag, N.; Hara, T.; Haser, J.; Hofmann, M.; Horton-Smith, Glenn A.; Hourlier, A.; Ishitsuka, M.; Jochum, J.; Jollet, C.; Kaether, F.; Kalousis, L. N.; Kamyshkov, Y.; Kaplan, D. M.; Kawasaki, T.; Kemp, E.; de Kerret, H.; Kryn, D.; Kuze, M.; Lachenmaier, Tobias; Lane, C. E.; Lasserre, T.; Letourneau, A.; Lhuillier, D.; Lima, H. P., Jr.; Lindner, M.; Lopez-Castano, J. M.; LoSecco, J. M.; Lubsandorzhiev, B. K.; Lucht, S.; Maeda, J.; Mariani, Camillo; Maricic, Jelena; Martino, J.; Matsubara, T.; Mention, G.; Meregaglia, A.; Miletic, T.; Milincic, R.; Minotti, A.; Nagasaka, Y.; Nikitenko, Y.; Novella, P.; Oberauer, L.; Obolensky, M.; Onillon, A.; Osborn, A.; Palomares, C.; Pepe, I. M.; Perasso, S.; Pfahler, P.; Porta, A.; Pronost, G.; Reichenbacher, J.; Reinhold, B.; Roehling, M.; Roncin, R.; Roth, S.; Rybolt, B.; Sakamoto, Y.; Santorelli, R.; Schilithz, A. C.; Schoenert, S.; Schoppmann, S.; Shaevitz, Marjorie Hansen; Sharankova, R.; Shimojima, S.; Shrestha, D.; Sibille, V.; Sinev, V.; Skorokhvatov, Mikhail D.; Smith, E.; Spitz, Joshua; Stahl, A.; Stancu, Ion; Stokes, Lee F. F.; Strait, M.; Stuken, A.; Suekane, F.; Sukhotin, S.; Sumiyoshi, T.; Sun, Y.; Svoboda, R.; Terao, K.; Tonazzo, A.; Thi, H. H. Trinh; Valdiviesso, G. A.; Vassilopoulos, N.; Veyssiere, C.; Vivier, M.; Wagner, S.; Walsh, N.; Watanabe, H.; Wiebusch, C.; Winslow, L.; Wurm, M.; Yang, G.; Yermia, F.; Zimmer, V. (Springer, 2014-10-06)
    The Double Chooz experiment measures the neutrino mixing angle theta(13) by detecting reactor (nu) over bar (e) via inverse beta decay. The positron-neutron space and time coincidence allows for a sizable background rejection, nonetheless liquid scintillator detectors would profit from a positron/electron discrimination, if feasible in large detector, to suppress the remaining background. Standard particle identification, based on particle dependent time profile of photon emission in liquid scintillator, can not be used given the identical mass of the two particles. However, the positron annihilation is sometimes delayed by the orthopositronium (o-Ps) metastable state formation, which induces a pulse shape distortion that could be used for positron identification. In this paper we report on the first observation of positronium formation in a large liquid scintillator detector based on pulse shape analysis of single events. The o-Ps formation fraction and its lifetime were measured, finding the values of 44 +/- 12 % (sys.) +/- 5 % (stat.) and 3.68 ns +/- 0.17 ns (sys.) +/- 0.15 ns (stat.) respectively, in agreement with the results obtained with a dedicated positron annihilation lifetime spectroscopy setup.
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    Reactor (nu)over-bar(e) disappearance in the Double Chooz experiment
    Abe, Y.; Aberle, C.; dos Anjos, J. C.; Barriere, J. C.; Bergevin, M.; Bernstein, A.; Bezerra, T. J. C.; Bezrukhov, Leonid B.; Blucher, E.; Bowden, N. S.; Buck, C.; Busenitz, J.; Cabrera, A.; Caden, E.; Camilleri, Leslie; Carr, Rachel E.; Cerrada, M.; Chang, P. J.; Chimenti, P.; Classen, T.; Collin, A. P.; Conover, E.; Conrad, Janet M.; Crespo-Anadon, J. I.; Crum, K.; Cucoanes, A. S.; D'Agostino, M. V.; Damon, E.; Dawson, J. V.; Dazeley, S.; Dietrich, D.; Djurcic, Zelimir; Dracos, M.; Durand, V.; Ebert, J.; Efremenko, Y.; Elnimr, M.; Etenko, A.; Fallot, M.; Fechner, M.; von Feilitzsch, F.; Felde, J.; Franco, D.; Franke, A. J.; Franke, M.; Furuta, H.; Gama, R.; Gil-Botella, I.; Giot, L.; Goger-Neff, M.; Gonzalez, L. F. G.; Goodman, M. C.; Goon, J. T. M.; Greiner, D.; Haag, N.; Hagner, C.; Hara, T.; Hartmann, F. X.; Haser, J.; Hatzikoutelis, A.; Hayakawa, T.; Hofmann, M.; Horton-Smith, Glenn A.; Hourlier, A.; Ishitsuka, M.; Jochum, J.; Jollet, C.; Jones, C. L.; Kaether, F.; Kalousis, L. N.; Kamyshkov, Y.; Kaplan, D. M.; Kawasaki, T.; Keefer, G.; Kemp, E.; de Kerret, H.; Kibe, Y.; Konno, T.; Kryn, D.; Kuze, M.; Lachenmaier, Tobias; Lane, C. E.; Langbrandtner, C.; Lasserre, T.; Letourneau, A.; Lhuillier, D.; Lima, H. P.; Lindner, M.; Lopez-Castano, J. M.; LoSecco, J. M.; Lubsandorzhiev, B. K.; Lucht, S.; McKee, D.; Maeda, J.; Maesano, C. N.; Mariani, Camillo; Maricic, Jelena; Martino, J.; Matsubara, T.; Mention, G.; Meregaglia, A.; Miletic, T.; Milincic, R.; Miyata, H.; Mueller, T. A.; Nagasaka, Y.; Nakajima, K.; Novella, P.; Obolensky, M.; Oberauer, L.; Onillon, A.; Osborn, A.; Ostrovskiy, I.; Palomares, C.; Pepe, I. M.; Perasso, S.; Perrin, P.; Pfahler, P.; Porta, A.; Potzel, W.; Reichenbacher, J.; Reinhold, B.; Remoto, A.; Roehling, M.; Roncin, R.; Roth, S.; Sakamoto, Y.; Santorelli, R.; Sato, F.; Schoenert, S.; Schoppmann, S.; Schwetz, T.; Shaevitz, Marjorie Hansen; Shimojima, S.; Shrestha, D.; Sida, J. L.; Sinev, V.; Skorokhvatov, Mikhail D.; Smith, E.; Spitz, Joshua; Stahl, A.; Stancu, Ion; Stokes, Lee F. F.; Strait, M.; Stuken, A.; Suekane, F.; Sukhotin, S.; Sumiyoshi, T.; Sun, Y.; Svoboda, R.; Terao, K.; Tonazzo, A.; Toups, M.; Thi, H. H. T.; Valdiviesso, G. A.; Veyssiere, C.; Wagner, S.; Watanabe, H.; White, B.; Wiebusch, C.; Winslow, L.; Worcester, M.; Wurm, M.; Yermia, F.; Zimmer, V.; Double Chooz, Collaboration (American Physical Society, 2012-09-18)
    The Double Chooz experiment has observed 8249 candidate electron antineutrino events in 227.93 live days with 33.71 GW-ton-years (reactor power X detector mass X live time) exposure using a 10.3 m(3) fiducial volume detector located at 1050 m from the reactor cores of the Chooz nuclear power plant in France. The expectation in case of theta(13) = 0 is 8937 events. The deficit is interpreted as evidence of electron antineutrino disappearance. From a rate plus spectral shape analysis we find sin(2)2 theta(13) = 0.109 +/- 0.030(stat) +/- 0.025(syst). The data exclude the no-oscillation hypothesis at 99.8% CL (2.9 sigma).