461 research outputs found

    CP, T and CPT violation in future long baseline experiments

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    I give a short overview about the possibilities and problems related to the measurement of CP violation in long baseline experiments. Special attention is paid to the issue of degeneracies and a method for their resolution is quantitatively discussed. The CP violation reach for different experiments is compared in dependence of sin⁥22θ13\sin^22\theta_{13} and \dm{21}. Furthermore a short comment about the possible effects of matter induced T violation is made. Finally the limits on CPT violation obtainable at a neutrino factory are shown.Comment: Talk presented at NUFACT02, London, 1-6 July, 2002. 3 pages, 2 figure

    Physics Potential of the SPL Super Beam

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    Performances of a neutrino beam generated by the CERN SPL proton driver are computed considering a 440 kton water Cerenkov detector at 130 km from the target. θ13\theta_{13} sensitivity down to 1.2∘1.2^\circ and a δ\delta sensitivity comparable to a Neutrino Factory, for θ13≥3∘\theta_{13} \geq 3^\circ, are within the reach of such a project.Comment: Invited talk at the Nufact02 Workshop, Imperial College of Science, Technology and Medicine, London, July 200

    Unveiling Neutrino Mixing and Leptonic CP Violation

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    We review the present understanding of neutrino masses and mixings, discussing what are the unknowns in the three family oscillation scenario. Despite the anticipated success coming from the planned long baseline neutrino experiments in unraveling the leptonic mixing sector, there are two important unknowns which may remain obscure: the mixing angle θ13\theta_{13} and the CP-phase δ\delta. The measurement of these two parameters has led us to consider the combination of superbeams and neutrino factories as the key to unveil the neutrino oscillation picture.Comment: Invited brief review, 18 pages, 6 figure

    Untangling CP Violation and the Mass Hierarchy in Long Baseline Experiments

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    In the overlap region, for the normal and inverted hierarchies, of the neutrino-antineutrino bi-probability space for νμ→νe\nu_\mu \to \nu_e appearance, we derive a simple identity between the solutions in the (sin⁡22θ13\sin^2 2\theta_{13}, sin⁡δ\sin \delta) plane for the different hierarchies. The parameter sin⁡22θ13\sin^2 2\theta_{13} sets the scale of the νμ→νe\nu_\mu \to \nu_e appearance probabilities at the atmospheric δmatm2≈2.4×10−3\delta m^2_{atm} \approx 2.4 \times 10^{-3} eV2^2 whereas sin⁡δ\sin \delta controls the amount of CP violation in the lepton sector. The identity between the solutions is that the difference in the values of sin⁡δ\sin \delta for the two hierarchies equals twice the value of sin⁡22θ13\sqrt{\sin^2 2\theta_{13}} divided by the {\it critical} value of sin⁡22θ13\sqrt{\sin^2 2\theta_{13}}. We apply this identity to the two proposed long baseline experiments, T2K and NOν\nuA, and we show how it can be used to provide a simple understanding of when and why fake solutions are excluded when two or more experiments are combined. The identity demonstrates the true complimentarity of T2K and NOν\nuA.Comment: 15 pages, Latex, 4 postscript figures. Submitted to New Journal of Physics, ``Focus on Neutrino Physics'' issu

    Neutrino Factories and the "Magic" Baseline

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    We show that for a neutrino factory baseline of L∼7300km−7600kmL \sim 7300 km - 7 600 km a ``clean'' measurement of sin⁡22θ13\sin^2 2 \theta_{13} becomes possible, which is almost unaffected by parameter degeneracies. We call this baseline "magic" baseline, because its length only depends on the matter density profile. For a complete analysis, we demonstrate that the combination of the magic baseline with a baseline of 3000 km is the ideal solution to perform equally well for the sin⁡22θ13\sin^2 2 \theta_{13}, sign of Δm312\Delta m_{31}^2, and CP violation sensitivities. Especially, this combination can very successfully resolve parameter degeneracies even below sin⁡22θ13<10−4\sin^2 2 \theta_{13} < 10^{-4}.Comment: Minor changes, final version to appear in PRD, 4 pages, 3 figures, RevTe

    Physics Potential of Very Intense Conventional Neutrino Beams

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    The physics potential of high intensity conventional beams is explored. We consider a low energy super beam which could be produced by a proposed new accelerator at CERN, the Super Proton Linac. Water Cherenkov and liquid oil scintillator detectors are studied as possible candidates for a neutrino oscillation experiment which could improve our current knowledge of the atmospheric parameters and measure or severely constrain the parameter connecting the atmospheric and solar realms. It is also shown that a very large water detector could eventually observe leptonic CP violation. The reach of such an experiment to the neutrino mixing parameters would lie in-between the next generation of neutrino experiments (MINOS, OPERA, etc) and a future neutrino factory.Comment: Talk given at the Venice Conference on Neutrino Telescopes, Venice, March, 200

    Study of the eightfold degeneracy with a standard β\beta-Beam and a Super-Beam facility

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    The study of the eightfold degeneracy at a neutrino complex that includes a standard β\beta-Beam and a Super-Beam facility is presented for the first time in this paper. The scenario where the neutrinos are sent toward a Megaton water Cerenkov detector located at the Fr\'{e}jus laboratory (baseline 130 Km) is exploited. The performance in terms of sensitivity for measuring the continuous (θ13\theta_{13} and δ\delta) and discrete (sign[Δm232]{sign} [ \Delta m^2_{23} ] and sign[tan⁡(2θ23)]{sign} [\tan (2\theta_{23}) ]) oscillation parameters for the β\beta-Beam and Super-Beam alone, and for their combination has been studied. A brief review of the present uncertainties on the neutrino and antineutrino cross-sections is also reported and their impact on the discovery potential discussed

    The Golden Channel at a Neutrino Factory revisited: improved sensitivities from a Magnetised Iron Neutrino Detector

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    This paper describes the performance and sensitivity to neutrino mixing parameters of a Magnetised Iron Neutrino Detector (MIND) at a Neutrino Factory with a neutrino beam created from the decay of 10 GeV muons. Specifically, it is concerned with the ability of such a detector to detect muons of the opposite sign to those stored (wrong-sign muons) while suppressing contamination of the signal from the interactions of other neutrino species in the beam. A new more realistic simulation and analysis, which improves the efficiency of this detector at low energies, has been developed using the GENIE neutrino event generator and the GEANT4 simulation toolkit. Low energy neutrino events down to 1 GeV were selected, while reducing backgrounds to the 10−410^{-4} level. Signal efficiency plateaus of ~60% for νμ\nu_\mu and ~70% for νˉμ\bar{\nu}_\mu events were achieved starting at ~5 GeV. Contamination from the νμ→ντ\nu_\mu\rightarrow \nu_\tau oscillation channel was studied for the first time and was found to be at the level between 1% and 4%. Full response matrices are supplied for all the signal and background channels from 1 GeV to 10 GeV. The sensitivity of an experiment involving a MIND detector of 100 ktonnes at 2000 km from the Neutrino Factory is calculated for the case of sin⁡22θ13∼10−1\sin^2 2\theta_{13}\sim 10^{-1}. For this value of θ13\theta_{13}, the accuracy in the measurement of the CP violating phase is estimated to be ΔδCP∼3∘−5∘\Delta \delta_{CP}\sim 3^\circ - 5^\circ, depending on the value of δCP\delta_{CP}, the CP coverage at 5σ5\sigma is 85% and the mass hierarchy would be determined with better than 5σ5\sigma level for all values of δCP\delta_{CP}

    Toroidal magnetized iron neutrino detector for a neutrino factory

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    A neutrino factory has unparalleled physics reach for the discovery and measurement of CP violation in the neutrino sector. A far detector for a neutrino factory must have good charge identification with excellent background rejection and a large mass. An elegant solution is to construct a magnetized iron neutrino detector (MIND) along the lines of MINOS, where iron plates provide a toroidal magnetic field and scintillator planes provide 3D space points. In this paper, the current status of a simulation of a toroidal MIND for a neutrino factory is discussed in light of the recent measurements of large θ13. The response and performance using the 10 GeV neutrino factory configuration are presented. It is shown that this setup has equivalent δCP reach to a MIND with a dipole field and is sensitive to the discovery of CP violation over 85% of the values of δCP

    Use-wear and residue analysis of pounding tools used by wild capuchin monkeys (Sapajus libidinosus) from Serra da Capivara (PiauĂ­, Brazil)

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    Bearded capuchin monkeys (Sapajus libidinosus) from Serra da Capivara National Park (Brazil), perform the widest range of activities using stone tools of all the non-human tool-using primates. The behaviours behind this range of tool-use have been closely documented, but little is known about the characteristics of the tools themselves. Here we redress this imbalance and adopt an archaeological perspective to the analysis of capuchin pounding tools. We apply, for the first time, systematic microscopic techniques to the analysis of capuchin stone tools used for digging, cracking cashew nuts and seed processing to characterise their damage patterns combined with residue spatial distribution and micro-remains analysis. This work presents a standardized methodology for future primate archaeological use-wear studies as well as forming a reference collection which can be used to identify different activities within the primate archaeological record. Furthermore, understanding the archaeologically visible traces of primate percussive behaviours represents an initial step in developing a methodology to investigate if similar activities were practiced by early hominins and to help identify these activities in the Plio-Pleistocene archaeological record
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