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Search Results: 1 - 10 of 325226 matches for " S. Schoenert "
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Two particle states, lepton mixing and oscillations
M. Kachelriess,E. Resconi,S. Schoenert
Physics , 2001,
Abstract: Discussions of lepton mixing and oscillations consider generally only flavor oscillations of neutrinos and neglect the accompanying charged leptons. In cases of experimental interest like pion or nuclear beta decay an oscillation pattern is expected indeed only for neutrinos if only one of the two produced particles is observed. We argue that flavor oscillations of neutrinos without detecting the accompanying lepton is a peculiarity of the two-particle states $|l\nu>$ produced in pion or nuclear beta decay. Generally, an oscillation pattern is only found if both particles are detected. We discuss in a pedagogical way how this distinction of the neutrinos arises, although on the level of the Lagrangian lepton mixing does not single them out against charged leptons. As examples, we discuss the difference between the state $|l\nu>$ produced by the decay of real $W$ boson and a $W$ originating from pion decay.
Solar and Reactor Neutrinos: Upcoming Experiments and Future Projects
Stefan Schoenert
Physics , 2002, DOI: 10.1016/S0920-5632(02)01491-3
Abstract: Sub-MeV solar neutrino experiments and long-baseline reactor oscillation experiments toe the cutting edge of neutrino research. The upcoming experiments KamLAND and BOREXINO, currently in their startup and final construction phase respectively, will provide essential information on neutrino properties as well as on solar physics. Future projects, at present under development, will measure the primary solar neutrino fluxes via electron scattering and neutrino capture in real time. High precision data for lepton mixing as well as for stellar evolution theory will become available in the future. This paper aims to give an overview of the upcoming experiments and of the projects under development.
Optical properties of bialkali photocathodes
Dario Motta,Stefan Schoenert
Physics , 2004, DOI: 10.1016/j.nima.2004.10.009
Abstract: The optical properties of the `bialkali' KCsSb and RbCsSb photomultiplier cathodes have been experimentally investigated in the visible range. The measurements carried out include the absolute reflectance at near-normal incidence, the polarization-dependent relative reflectance at various angles and the change in polarization upon reflection from the photocathode. These experimental inputs have been combined with a theoretical model to determine the complex refractive index of the photocathodes in the wavelength range 380 to 680 nm and their thickness. As a result of this work, we derive a model which predicts the fraction of light impinging on a photomultiplier tube that is reflected, absorbed or transmitted, as a function of wavelength and angle, and dependent on the medium to which the photomultiplier is coupled.
The HLMA project: determination of high delta-m^2 LMA mixing parameters and constraint on |U_e3| with a new reactor neutrino experiment
Stefan Schoenert,Thierry Lasserre,Lothar Oberauer
Physics , 2002, DOI: 10.1016/S0927-6505(02)00181-0
Abstract: In the forthcoming months, the KamLAND experiment will probe the parameter space of the solar large mixing angle (LMA) MSW solution as the origin of the solar neutrino deficit with $\nuebar$'s from distant nuclear reactors. If however the solution realized in nature is such that $\Dm2_{sol} \gsim 2 \cdot 10^{-4}$ eV$^2$ (thereafter named the HLMA region), KamLAND will only observe a rate suppression but no spectral distortion and hence it will not have the optimal sensitivity to measure the mixing parameters. In this case, we propose a new medium baseline reactor experiment located at Heilbronn (Germany) to pin down the precise value of the solar mixing parameters. In this paper, we present the Heilbronn detector site, we calculate the $\nuebar$ interaction rate and the positron spectrum expected from the surrounding nuclear power plants. We also discuss the sensitivity of such an experiment to |U_e3| in both normal and inverted neutrino mass hierarchy scenarios. We then outline the detector design, estimate background signals induced by natural radioactivity as well as by in-situ cosmic ray muon interaction, and discuss a strategy to detect the anti-neutrino signal 'free of background'.
A proposed search for a fourth neutrino with a PBq antineutrino source
Michel Cribier,Maximilien Fechner,Thierry Lasserre,Alain Letourneau,David Lhuillier,Guillaume Mention,Davide Franco,Vasily Kornoukhov,Stefan Schoenert
Physics , 2011, DOI: 10.1103/PhysRevLett.107.201801
Abstract: Several observed anomalies in neutrino oscillation data can be explained by a hypothetical fourth neutrino separated from the three standard neutrinos by a squared mass difference of a few eV^2. We show that this hypothesis can be tested with a PBq (ten kilocurie scale) 144Ce or 106Ru antineutrino beta-source deployed at the center of a large low background liquid scintillator detector. In particular, the compact size of such a source could yield an energy-dependent oscillating pattern in event spatial distribution that would unabiguously determine neutrino mass differences and mixing angles.
A New 76Ge Double Beta Decay Experiment at LNGS
I. Abt,M. Altmann,A. Bakalyarov,I. Barabanov,C. Bauer,E. Bellotti,S. T. Belyaev,L. Bezrukov,V. Brudanin,C. Buettner,V. P. Bolotsky,A. Caldwell,C. Cattadori,H. Clement,A. Di Vacri,J. Eberth,V. Egorov,G. Grigoriev,V. Gurentsov,K. Gusev,W. Hampel,G. Heusser,W. Hofmann,J. Jochum,M. Junker,J. Kiko,I. V. Kirpichnikov,A. Klimenko,K. T. Knoepfle,V. N. Kornoukhov,M. Laubenstein,V. Lebedev,X. Liu,I. Nemchenok,L. Pandola,V. Sandukovsky,S. Schoenert,S. Scholl,B. Schwingenheuer,H. Simgen,A. Smolnikov,A. Tikhomirov,A. A. Vasenko,S. Vasiliev,D. Weisshaar,E. Yanovich,J. Yurkowski,S. Zhukov,G. Zuzel
Physics , 2004,
Abstract: This Letter of Intent has been submitted to the Scientific Committee of the INFN Laboratori Nazionali del Gran Sasso (LNGS) in March 2004. It describes a novel facility at the LNGS to study the double beta decay of 76Ge using an (optionally active) cryogenic fluid shield. The setup will allow to scrutinize with high significance on a short time scale the current evidence for neutrinoless double beta decay of 76Ge using the existing 76Ge diodes from the previous Heidelberg-Moscow and IGEX experiments. An increase in the lifetime limit can be achieved by adding more enriched detectors, remaining thereby background-free up to a few 100 kg-years of exposure.
Letter of Intent for Double-CHOOZ: a Search for the Mixing Angle Theta13
F. Ardellier,I. Barabanov,J. C. Barriere,M. Bauer,L. Bezrukov,C. Buck,C. Cattadori,B. Courty,M. Cribier,F. Dalnoki-Veress,N. Danilov,H. de Kerret,A. Di Vacri,A. Etenko,M. Fallot,Ch. Grieb,M. Goeger,A. Guertin,T. Kirchner,Y. S. Krylov,D. Kryn,C. Hagner,W. Hampel,F. X. Hartmann,P. Huber,J. Jochum,T. Lachenmaier,Th. Lasserre,Ch. Lendvai,M. Lindner,F. Marie,J. Martino,G. Mention,A. Milsztajn,J. P. Meyer,D. Motta,L. Oberauer,M. Obolensky,L. Pandola,W. Potzel,S. Schoenert,U. Schwan,T. Schwetz,S. Scholl,L. Scola,M. Skorokhvatov,S. Sukhotin,A. Letourneau,D. Vignaud,F. von Feilitzsch,W. Winter,E. Yanovich
Physics , 2004,
Abstract: Tremendous progress has been achieved in neutrino oscillation physics during the last few years. However, the smallness of the $\t13$ neutrino mixing angle still remains enigmatic. The current best constraint comes from the CHOOZ reactor neutrino experiment $\s2t13 < 0.2$ (at 90% C.L., for $\adm2=2.0 10^{-3} \text{eV}^2$). We propose a new experiment on the same site, Double-CHOOZ, to explore the range of $\s2t13$ from 0.2 to 0.03, within three years of data taking. The improvement of the CHOOZ result requires an increase in the statistics, a reduction of the systematic error below one percent, and a careful control of the cosmic ray induced background. Therefore, Double-CHOOZ will use two identical detectors, one at $\sim$150 m and another at 1.05 km distance from the nuclear cores. The plan is to start data taking with two detectors in 2008, and to reach a sensitivity of 0.05 in 2009, and 0.03 in 2011.
Complete results for five years of GNO solar neutrino observations
GNO COLLABORATION,M. Altmann,M. Balata,P. Belli,E. Bellotti,R. Bernabei,E. Burkert,C. Cattadori,R. Cerulli,M. Chiarini,M. Cribier,S. d'Angelo,G. Del Re,K. H. Ebert,F. v. Feilitzsch,N. Ferrari,W. Hampel,F. X. Hartmann,E. Henrich,G. Heusser,F. Kaether,J. Kiko,T. Kirsten,T. Lachenmaier,J. Lanfranchi,M. Laubenstein,K. Luetzenkirchen,K. Mayer,P. Moegel,D. Motta,S. Nisi,J. Oehm,L. Pandola,F. Petricca,W. Potzel,H. Richter,S. Schoenert,M. Wallenius,M. Wojcik,L. Zanotti
Statistics , 2005, DOI: 10.1016/j.physletb.2005.04.068
Abstract: We report the complete GNO solar neutrino results for the measuring periods GNO III, GNO II, and GNO I. The result for GNO III (last 15 solar runs) is [54.3 + 9.9 - 9.3 (stat.)+- 2.3 (syst.)] SNU (1 sigma) or [54.3 + 10.2 - 9.6 (incl. syst.)] SNU (1 sigma) with errors combined. The GNO experiment is now terminated after altogether 58 solar exposure runs that were performed between May 20, 1998 and April 9, 2003. The combined result for GNO (I+II+III) is [62.9 + 5.5 - 5.3 (stat.) +- 2.5 (syst.)] SNU (1 sigma) or [62.9 + 6.0 - 5.9] SNU (1 sigma) with errors combined in quadrature. Overall, gallium based solar observations at LNGS (first in GALLEX, later in GNO) lasted from May 14, 1991 through April 9, 2003. The joint result from 123 runs in GNO and GALLEX is [69.3 +- 5.5 (incl. syst.)] SNU (1 sigma). The distribution of the individual run results is consistent with the hypothesis of a neutrino flux that is constant in time. Implications from the data in particle- and astrophysics are reiterated.
Solar neutrino physics with Borexino I
L. Ludhova,G. Bellini,J. Benziger,D. Bick,G. Bonfini,D. Bravo,M. Buizza Avanzini,B. Caccianiga,L. Cadonati,F. Calaprice,C. Carraro,P. Cavalcante,A. Chavarria,D. D'Angelo,S. Davini,A. Derbin,A. Etenko,K. Fomenko,D. Franco,C. Galbiati,S. Gazzana,C. Ghiano,M. Giammarchi,M. Goeger-Nef,A. Goretti,L. Grandi,E. Guardincerri,S. Hardy,Aldo Ianni,Andrea Ianni,A. Kayunov,V. Kobychev,D. Korablev,G. Korga,Y. Koshio,D. Kryn,M. Laubenstein,T. Lewke,E. Litvinovich,B. Loer,F. Lombardi,P. Lombardi,I. Machulin,S. Manecki,W. Maneschg,G. Manuzio,Q. Meindl,E. Meroni,L. Miramonti,M. Misiaszek,D. Montanari,P. Mosteiro,V. Muratova,L. Oberauer,M. Obolenksy,F. Ortica,K. Otis,M. Pallavicini,L. Papp,L. Perasso,S. Perasso,A. Pocar,R. S. Raghavan,G. Ranucci,A. Razeto,A. Re,P. A. Romani,A. Sabelnikov,R. Saldanha,C. Salvo,S. Schoenert,H. Simgen,M. Skorokhvatov,O. Smirnov,A. Sotnikov,S. Sukhotin,Y. Suvorov,R. Tartaglia,G. Testera,D. Vignaud,R. B. Vogelaar,F. Von Feilitzsch,J. Winter,M. Wojcik,A. Wright,M. Wurm,J. Xu,O. Zaimidoroga,S. Zavatarelli,G. Zuzel
Physics , 2012,
Abstract: Borexino is a large-volume liquid scintillator detector installed in the underground halls of the Laboratori Nazionali del Gran Sasso in Italy. After several years of construction, data taking started in May 2007. The Borexino phase I ended after about three years of data taking. Borexino provided the first real time measurement of the $^{7}$Be solar neutrino interaction rate with accuracy better than 5% and confirmed the absence of its day-night asymmetry with 1.4% precision. This latter Borexino results alone rejects the LOW region of solar neutrino oscillation parameters at more than 8.5 $\sigma$ C.L. Combined with the other solar neutrino data, Borexino measurements isolate the MSW-LMA solution of neutrino oscillations without assuming CPT invariance in the neutrino sector. Borexino has also directly observed solar neutrinos in the 1.0-1.5 MeV energy range, leading to the first direct evidence of the $pep$ solar neutrino signal and the strongest constraint of the CNO solar neutrino flux up to date. Borexino provided the measurement of the solar $^{8}$B neutrino rate with 3 MeV energy threshold.
Measurement of the half-life of the two-neutrino double beta decay of Ge-76 with the Gerda experiment
GERDA Collaboration,M. Agostini,M. Allardt,E. Andreotti,A. M. Bakalyarov,M. Balata,I. Barabanov,M. Barnabe Heider,N. Barros,L. Baudis,C. Bauer,N. Becerici-Schmidt,E. Bellotti,S. Belogurov,S. T. Belyaev,G. Benato,A. Bettini,L. Bezrukov,T. Bode,V. Brudanin,R. Brugnera,D. Budjas,A. Caldwell,C. Cattadori,A. Chernogorov,F. Cossavella,E. V. Demidova,A. Denisov,A. Domula,V. Egorov,R. Falkenstein,A. D. Ferella,K. Freund,F. Froborg,N. Frodyma,A. Gangapshev,A. Garfagnini,S. Gazzana,P. Grambayr,V. Gurentsov,K. Gusev,K. K. Guthikonda,W. Hampel,A. Hegai,M. Heisel,S. Hemmer,G. Heusser,W. Hofmann,M. Hult,L. V. Inzhechik,L. Ioannucci,J. Janicsko Csathy,J. Jochum,M. Junker,S. Kianovsky,I. V. Kirpichnikov,A. Kirsch,A. Klimenko,K. T. Knoepfle,O. Kochetov,V. N. Kornoukhov,V. Kusminov,M. Laubenstein,A. Lazzaro,V. I. Lebedev,B. Lehnert,H. Y. Liao,M. Lindner,I. Lippi,X. Liu,A. Lubashevskiy,B. Lubsandorzhiev,G. Lutter,A. A. Machado,B. Majorovits,W. Maneschg,I. Nemchenok,S. Nisi,C. O'Shaughnessy,L. Pandola,K. Pelczar,L. Peraro,A. Pullia,S. Riboldi,F. Ritter,C. Sada,M. Salathe,C. Schmitt,S. Schoenert,J. Schreiner,O. Schulz,B. Schwingenheuer,E. Shevchik,M. Shirchenko,H. Simgen,A. Smolnikov,L. Stanco,H. Strecker,M. Tarka,C. A. Ur,A. A. Vasenko,O. Volynets,K. von Sturm,M. Walter,A. Wegmann,M. Wojcik,E. Yanovich,P. Zavarise,I. Zhitnikov,S. V. Zhukov,D. Zinatulina,K. Zuber,G. Zuzel
Physics , 2012, DOI: 10.1088/0954-3899/40/3/035110
Abstract: The primary goal of the GERmanium Detector Array (Gerda) experiment at the Laboratori Nazionali del Gran Sasso of INFN is the search for the neutrinoless double beta decay of Ge-76. High-purity germanium detectors made from material enriched in Ge-76 are operated directly immersed in liquid argon, allowing for a substantial reduction of the background with respect to predecessor experiments. The first 5.04 kg yr of data collected in Phase I of the experiment have been analyzed to measure the half-life of the neutrino-accompanied double beta decay of Ge-76. The observed spectrum in the energy range between 600 and 1800 keV is dominated by the double beta decay of Ge-76. The half-life extracted from Gerda data is T(1/2) = (1.84 +0.14 -0.10) 10^{21} yr.
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