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Background Study on nu_e Appearance from a nu_mu Beam in Very Long Baseline Neutrino Oscillation Experiments with a Large Water Cherenkov Detector  [PDF]
Chiaki Yanagisawa,Chang Kee Jung,Trung Le,Brett Viren
Physics , 2010, DOI: 10.1103/PhysRevD.83.072002
Abstract: There is a growing interest in very long baseline neutrino oscillation experimentation using accelerator produced neutrino beam as a machinery to probe the last three unmeasured neutrino oscillation parameters: the mixing angle theta_13, the possible CP violating phase delta_CP and the mass hierarchy, namely, the sign of delta-m^2_32. Water Cherenkov detectors such as IMB, Kamiokande and Super-Kamiokande have shown to be very successful at detecting neutrino interactions. Scaling up this technology may continue to provide the required performance for the next generation of experiments. This report presents the latest effort to demonstrate that a next generation (> 100 kton) water Cherenkov detector can be used effectively for the rather difficult task of detecting nu_e events from the neutrino oscillation nu_mu -> nu_e despite the large expected potential background resulting from pi^0 events produced via neutral current interactions.
Long-baseline neutrino oscillation experiments and CP violation in the lepton sector  [PDF]
S. M. Bilenky,C. Giunti,W. Grimus
Physics , 1997, DOI: 10.1103/PhysRevD.58.033001
Abstract: We discuss possibilities to investigate the effects of CP (and T) violation in the lepton sector in neutrino oscillation experiments. We consider the effects of CP violation in the framework of two schemes of mixing of four massive neutrinos that can accommodate the results of all neutrino oscillation experiments. Using the constraints on the mixing parameters that follow from the results of short-baseline neutrino oscillation experiments, we derive rather strong upper bounds on the effects of CP violation in nu_mu<->nu_e transitions in long-baseline neutrino oscillation experiments. We show that the effects of CP violation in nu_mu<->nu_tau transitions in long-baseline oscillation experiments can be as large as is allowed by the unitarity of the mixing matrix. The matter effects, which complicate the problem of searching for CP violation in long-baseline experiments, are discussed in detail. We consider the T-odd asymmetries whose measurement could allow to reveal T and CP violation in the lepton sector independently from matter effects.
Bounds on long-baseline nu_e->nu_e and nu_mu->nu_e transition probabilities  [PDF]
S. M. Bilenky,C. Giunti,W. Grimus
Physics , 1997, DOI: 10.1103/PhysRevD.57.1920
Abstract: We discuss long-baseline neutrino oscillations in the framework of the two 4-neutrino schemes which can accommodate all existing neutrino oscillation data. Negative results of short-baseline reactor and accelerator experiments allow to obtain rather strong bounds on the long-baseline nu_e->nu_e and nu_mu->nu_e transition probabilities. We consider in detail matter effects and show that the vacuum bounds are not substantially modified. We also comment on corresponding bounds in 3-neutrino scenarios.
Multi-ring signatures of the oscillation nu_mu --> nu_e in a water Cherenkov detector  [PDF]
A. Asratyan,G. Davidenko,A. Dolgolenko,V. Kaftanov,M. Kubantsev,V. Verebryusov
Physics , 2003, DOI: 10.1140/epjc/s2003-01285-2
Abstract: Multiring signatures of the oscillation nu_mu --> nu_e are formulated for a water Cherenkov detector. These are appropriate for relatively high neutrino energies (over 2 GeV) that emphasize the matter effect and, therefore, may allow to measure the sign of the atmospheric mass-squared difference.
Oscillation Measurements with Upgraded Conventional Neutrino Beams  [PDF]
V. Barger
Physics , 2001,
Abstract: We consider the nu_mu to nu_e oscillation measurements that would be possible at upgraded 1 GeV and multi-GeV conventional neutrino sources driven by future megawatt-scale proton drivers. If these neutrino superbeams are used together with detectors that are an order of magnitude larger than those presently foreseen, we find that the sensitivity to nu_mu to nu_e oscillations can be improved by an order of magnitude beyond the next generation of accelerator based experiments. In addition, over a limited region of parameter space, the neutrino mass hierarchy can be determined with a multi-GeV long baseline beam. If the Large Mixing Angle MSW solution correctly describes the solar neutrino deficit, there is a small corner of allowed parameter space in which maximal CP-violation in the lepton sector might be observable at a 1 GeV medium baseline experiment. Superbeams with massive detectors would therefore provide a useful tool en route to a neutrino factory, which would permit a further order of magnitude improvement in sensitivity, together with a more comprehensive check of CP-violation and the oscillation framework.
A letter of intent for an experiment to measure nu_mu to nu_e oscillations and nu_mu disappearance at the Fermilab Booster (BooNE)  [PDF]
E. Church,I. Stancu,G. J. VanDalen,R. A. Johnson,J. M. Conrad,J. Formaggio,T. Ochs,M. H. Shaevitz,E. G. Stern,B. Tamminga,D. Smith,G. T. Garvey,W. C. Louis,G. B. Mills,V. Sandberg,R. Tayloe,D. H. White,H. J. Kim,R. Imlay,W. Metcalf,N. Wadia,Z. D. Greenwood
Physics , 1997,
Abstract: This Letter of Intent to the Fermilab Program Advisory Committee describes a search for neutrino oscillations at the Fermilab booster. It is motivated by the LSND observation of nu_mu -> nu_e appearance. The booster neutrino experiment (BooNE) will be capable of observing both nu_mu -> nu_e appearance and nu_mu disappearance. In addition, the experiment will be able to measure Delta m^2 and sin^2(2theta) and search for CP violation in the lepton sector.
Testing Matter Effects in Very Long Baseline Neutrino Oscillation Experiments  [PDF]
M. Freund,M. Lindner,S. T. Petcov,A. Romanino
Physics , 1999, DOI: 10.1016/S0550-3213(00)00179-6
Abstract: Assuming three-neutrino mixing, we study the capabilities of very long baseline neutrino oscillation experiments to verify and test the MSW effect and to measure the lepton mixing angle theta_13. We suppose that intense neutrino and antineutrino beams will become available in so-called neutrino factories. We find that the most promising and statistically significant results can be obtained by studying nu_e ->nu_mu and \bar{nu}_e-> \bar{nu}_mu oscillations which lead to matter enhancements and suppressions of wrong sign muon rates. We show the theta_13 ranges where matter effects could be observed as a function of the baseline. We discuss the scaling laws of rates, significances and sensitivities with the relevant mixing angles and experimental parameters. Our analysis includes fluxes, event rates and statistical aspects so that the conclusions should be useful for the planning of experimental setups. We discuss the subleading Delta m^2_{21} effects in the case of the LMA MSW solution of the solar problem, showing that they are small for L >= 7000 km. For shorter baselines, Delta m^2_{21} effects can be relevant and their dependence on L offers a further handle for the determination of the CP-violation phase \delta. Finally we comment on the possibility to measure the specific distortion of the energy spectrum due to the MSW effect.
Final NOMAD results on nu_mu->nu_tau and nu_e->nu_tau oscillations including a new search for nu_tau appearance using hadronic tau decays  [PDF]
NOMAD Collaboration,P. Astier
Physics , 2001, DOI: 10.1016/S0550-3213(01)00339-X
Abstract: Results from the nu_tau appearance search in a neutrino beam using the full NOMAD data sample are reported. A new analysis unifies all the hadronic tau decays, significantly improving the overall sensitivity of the experiment to oscillations. The "blind analysis" of all topologies yields no evidence for an oscillation signal. In the two-family oscillation scenario, this sets a 90% C.L. allowed region in the sin^2(2theta)-Delta m^2 plane which includes sin^2(2theta)<3.3 x 10^{-4} at large Delta m^2 and Delta m^2 < 0.7 eV^2/c^4 at sin^2(2theta)=1. The corresponding contour in the nu_e->nu_tau oscillation hypothesis results in sin^2(2theta)<1.5 x 10^{-2} at large Delta m^2 and Delta m^2 < 5.9 eV^2/c^4 at sin^2(2theta)=1. We also derive limits on effective couplings of the tau lepton to nu_mu or nu_e.
Long Baseline Neutrino Physics: From Fermilab to Kamioka  [PDF]
Fritz DeJongh
Physics , 2002,
Abstract: We have investigated the physics potential of very long baseline experiments designed to measure nu_mu to nu_e oscillation probabilities. The principles of our design are to tune the beam spectrum to the resonance energy for the matter effect, and to have the spectrum cut off rapidly above this energy. The matter effect amplifies the signal, and the cut-off suppresses backgrounds which feed-down from higher energy. The signal-to-noise ratio is potentially better than for any other conventional nu_mu beam experiment. We find that a beam from Fermilab aimed at the Super-K detector has excellent sensitivity to sin^2(2theta_13) and the sign of Delta M^2. If the mass hierarchy is inverted, the beam can be run in antineutrino mode with a similar signal-to-noise ratio, and event rate 55% as high as for the neutrino mode. Combining the Fermilab beam with the JHF-Kamioka proposal adds very complementary information. We find good sensitivity to maximal CP violation for values of sin^2(2theta_13) ranging from 0.001 to 0.05.
Some conclusive considerations on the comparison of the ICARUS nu_mu to nu_e oscillation search with the MiniBooNE low-energy event excess  [PDF]
M. Antonello,B. Baibussinov,P. Benetti,F. Boffelli,A. Bubak,E. Calligarich,S. Centro,A. Cesana,K. Cieslik,D. B. Cline,A. G. Cocco,A. Dabrowska,A. Dermenev,A. Falcone,C. Farnese,A. Fava,A. Ferrari,D. Gibin,S. Gninenko,A. Guglielmi,M. Haranczyk,J. Holeczek,M. Kirsanov,J. Kisiel,I. Kochanek,J. Lagoda,S. Mania,A. Menegolli,G. Meng,C. Montanari,S. Otwinowski,P. Picchi,F. Pietropaolo,P. Plonski,A. Rappoldi,G. L. Raselli,M. Rossella,C. Rubbia,P. Sala,A. Scaramelli,F. Sergiampietri,D. Stefan,R. Sulej,M. Szarska,M. Terrani,M. Torti,F. Varanini,S. Ventura,C. Vignoli,H. Wang,X. Yang,A. Zalewska,A. Zani,K. Zaremba
Physics , 2015,
Abstract: A sensitive search for anomalous LSND-like nu_mu to nu_e oscillations has been performed by the ICARUS Collaboration exposing the T600 LAr-TPC to the CERN to Gran Sasso (CNGS) neutrino beam. The result is compatible with the absence of additional anomalous contributions giving a limit to oscillation probability of 3.4E-3 and 7.6E-3 at 90% and 99% confidence levels respectively showing a tension between these new limits and the low-energy event excess (200 < E_nu QE < 475 MeV) reported by MiniBooNE Collaboration. A more detailed comparison of the ICARUS data with the MiniBooNE low-energy excess has been performed, including the energy resolution as obtained from the official MiniBooNE data release. As a result the previously reported tension is confirmed at 90% C.L., suggesting an unexplained nature or an otherwise instrumental effect for the MiniBooNE low energy event excess
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