1,721,079 research outputs found
Borexino
No full textBorexino is a massive calorimetric liquid scintillation detector whose installation has been completed in the underground Gran Sasso Laboratory. The focus of the experiment is on the direct and real time measurement of the flux of neutrinos produced in the 7Be electron capture reaction in the Sun. Furthermore, recent studies about the reduction of the 11C background through suitable rejection techniques demonstrated the possibility to open an interesting additional observation window in the energy region of the pep and CNO solar neutrinos. Beyond the solar neutrino program, the detector will be also a powerful observatory for antineutrinos from Supernovae, as well as for geoneutrinos, profiting from a very low background from nuclear reactors
CNO and pep neutrino spectroscopy in Borexino: measurement of the deep-underground production of cosmogenic 11C in an organic liquid scintillator
No full textProposal for an Electron Antineutrino Disappearance Search Using High-Rate 8Li Production and Decay
No full textThis paper introduces a novel, high-intensity source of electron antineutrinos from the production and subsequent decay of 8Li. When paired with an existing ~1 kton scintillator-based detector, this =6.4 MeV source opens a wide range of possible searches for beyond standard model physics via studies of the inverse beta decay interaction. In particular, the experimental design described here has unprecedented sensitivity to electron antineutrino disappearance at 1 eV and features the ability to distinguish between the existence of zero, one, and two sterile neutrinos
Measurement of pp-chain Solar Neutrinos with Borexino
No full textThe Borexino detector, located at the Laboratori Nazionali del Gran Sasso in Italy, is a liquid scintillator detector with a primary goal to measure low-energy neutrinos created in the core of the Sun. In comparison to photons which need around hundred thousand years to reach the surface of the Sun, solar neutrinos are able to reach the earth around eight minutes a er their creation. Thus, the solar neutrino measurement opens the window to understand the properties of the Sun, namely the fusion mechanisms (pp-chain and CNO cycle) or the metallicity problem, and generally to test the predictions of the standard solar model. Furthermore, it is possible to study neutrino oscillation parameters and search for non-standard interactions through the deviations from the Mikheyev- Smirnov-Wolfenstein-Large-Mixing-Angle scenario (MSW-LMA). To increase the sensitivity for pep and CNO neutrinos, the multivariate fit technique has been developed, which takes into account additional information of the radial and pulse shape distributions of events. The talk gives an introduction to the solar neutrino physics and discusses the recently published results for the pp, pep, 7Be and 8B neutrino rates as well as the perspective to measure the neutrinos from the CNO cycle. This talk is presented in the name of the Borexino Collaboration
Data selection strategy for solar neutrino analysis with Borexino
No full textThe Borexino collaboration has recently released the first simultaneous measurement of the interaction rates of pp, 7Be and pep solar neutrinos. This result was made possible by the unprecedented low background of the scintillator during Phase-II, together with new data analysis techniques. We present the data selection strategy of the Borexino solar neutrino analysis: we describe how we select the neutrino-like scintillation events according to event-based cuts which eliminate most of the external and cosmogenic backgrounds. We describe also how the spatial distribution of events and a β+/β− pulse shape discrimination variable are used in a multivariate fit approach to additionally constrain the residual cosmogenic 11C and external backgrounds
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Search for high energy 5.5 MeV solar axions with the complete Borexino dataset
No full textAbstract A search for solar axions and axion-like particles produced in the p + d → 3 He + A ( 5.5 MeV ) reaction was performed using the complete dataset of the Borexino detector (3995 days of measurement live-time). The following interaction processes have been considered: axion decay into two photons ( A → 2 γ ) , inverse Primakoff conversion on nuclei ( A + Z → γ + Z ), the Compton conversion of axions to photons ( A + e → e + γ ) and the axio-electric effect ( A + e + Z → e + Z ). Model-independent limits on product of axion–photon ( g A γ ), axion–electron ( g Ae ), and isovector axion–nucleon ( g 3 A N ) couplings are obtained: | g A γ × g 3 A N | ≤ 2.3 × 10 - 11 GeV - 1 and | g Ae × g 3 A N | ≤ 1.9 × 10 - 13 at m A < 1 MeV (90% c.l.). The Borexino results exclude new large regions of g A γ , and g Ae coupling constants and axion masses m A , and leads to constraints on the products | g A γ × m A | and | g Ae × m A | for the KSVZ- and the DFSZ-axion models
Variations on the Author
Full text link“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
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