1,721,005 research outputs found
Status and Prospects of the JUNO Experiment
No full textThe Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton multi-purpose liquid scintillator detector being built in a dedicated underground laboratory in China and expected to start data taking in 2021. Its main physics goal is the determination of the neutrino mass ordering using electron anti-neutrinos from two nuclear power plants at a baseline of about 53 km. With an unprecedented energy resolution of 3% at 1 MeV, JUNO will be able to determine the mass ordering with a significance of 3-4 sigma within six years of running. In addition, JUNO will also perform other important measurements in neutrino physics and astrophysics, such as estimating the solar oscillation parameters and the atmospheric mass splitting down to an accuracy of 1% or better.
In this talk JUNO's physics potential will be described, the status of its construction will be reviewed and a small excursion into its rich R&D program will be given
SOX - Towards the Detection of Sterile Neutrinos in Borexino : Beta Spectrum Modeling, Monte Carlo Development and Sensitivity Studies for the Sterile Neutrino Search in Borexino
No full textSeveral experiments have reported anomalies in the neutrino sector which might be explained by the existence of a fourth (sterile) neutrino with a squared mass difference of about 1 eV 2 to the other three active neutrinos. The SOX project is part of the experimental program of the Borexino experiment and seeks for a clarification of the observed anomalies. For that purpose an artificial antineutrino source ( 144 Ce− 144 Pr) and possibly neutrino source ( 51 Cr) will be deployed underneath the large low background detector Borexino. The detector pro- vides both energy and vertex resolution to observe a possible oscillation signature within the detector volume. The calculation of the antineutrino spectrum is based on existing theoreti- cal models and was performed within this thesis. The modeling includes several sub-leading corrections particularly such as finite size of the nucleus, screening of the atomic electrons and radiative effects. Related to this work, dedicated Monte Carlo generators have been de- veloped to simulate the inverse beta decay reaction and the (anti)neutrino elastic scattering off electrons. Based on a profile likelihood analysis, the sensitivity to the sterile neutrino search of the SOX project was evaluated. The results obtained from this analysis confirm that the currently allowed parameter regions for sterile neutrinos can be tested at 95% confi- dence level. Finally, an alternative concept for the sterile neutrino search is presented which is based on a cyclotron and a Beryllium target near Borexino (Borexino+IsoDAR)
Topological Track Reconstruction in Liquid Scintillator and LENA as a Far-Detector in an LBNO Experiment
No full textUnsegmented liquid scintillator (LSc) neutrino detectors have proven to be successful instruments of neutrino physics. They usually measure terrestrial and astrophysical low-energy (LE) neutrinos and antineutrinos with energies up to some tens of MeV. Designs for next-generation detectors based on this technology intend to use several tens of kilotons of LSc. Two examples are the Low Energy Neutrino Astronomy (LENA) project with 50 kt considered in Europe and the Jiangmen Underground Neutrino Observatory (JUNO) with 20 kt already under construction in China. A key factor to reach the scientific goals of these projects, e.g., the determination of the neutrino mass ordering (MO) in the case of JUNO, will be the efficient rejection of background from radioisotopes produced by cosmogenic muons. This requires accurate reconstructions of extended muon event topologies in the LSc volume.The first part of this work is about the implementation of a novel, iterative track reconstruction procedure for unsegmented LSc detectors and a basic evaluation of its performance with the LENA detector simulation. The ultimate goal of the new method is to reconstruct the spatial number density distribution of optical photon emissions. This will give access to a charged particle's differential energy loss dE / dx in LSc and resolve details of an event's topology, e.g., induced particle showers. Visual comparisons of reconstruction outcomes with Monte Carlo (MC) truths already provide evidence for this capability. First quantitative results were extracted from the 3D reconstruction data of fully-contained muons in the kinetic energy range from 1 to 10 GeV: Despite some well understood systematic effects in the current method to find start and end point of a track, resolutions ≲ 25 cm lateral to the reconstructed track were ascertained for these spots. The determined angular resolution of ∼1.4° at 1 GeV improves to ∼0.3° with rising muon energy. With the current analysis method, the relative energy resolution approximately follows 10% / Sqrt(E / 1 GeV) + 2%.The application of the new technique is not the limited to cosmogenic muons. Future advancements may allow the reconstruction of the complex event topologies of GeV neutrino interactions. Beyond the (usual) LE neutrino program, this case would open up a new range of applications for unsegmented LSc detectors. The second part of this work therefore investigates the performance of LENA in a long-baseline neutrino oscillation (LBNO) experiment with a conventional multi-GeV neutrino beam as proposed in the Large Apparatus for Grand Unification and Neutrino Astrophysics (LAGUNA)-LBNO design study: A 750 kW neutrino beam aiming over a distance of ∼2300 km from the Conseil Européen pour laRecherche Nucléaire (CERN) to the Pyhäsalmi mine in central Finland. The potential to discover the neutrino MO and leptonic CP-violation was studied with the General Long Baseline Experiment Simulator (GLoBES) package in combination with MC techniques. Assuming ten years of runtime equally shared between neutrino and antineutrino mode, only a low sensitivity to CP-violation was found. However, in the MO study, the inverted ordering (IO) (normal ordering (NO)) hypothesis could be rejected at true NO (IO) with a median sensitivity of 4.6-6.7σ (4.2-5.8σ), depending on the true value of the CP-violating phase δ_CP
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Die Spurrekonstruktion für das Driftröhren-Myon-Spektrometer des Neutrino-Experiments OPERA
No full textAppropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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