313 research outputs found

    Cryogenic silicon detectors with implanted contacts for the detection of visible photons using the Neganov-Luke Effect

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    There is a common need in astroparticle experiments such as direct dark matter detection, 0{\nu}\b{eta}\b{eta} (double beta decay without emission of neutrinos) and Coherent Neutrino Nucleus Scattering experiments for light detectors with a very low energy threshold. By employing the Neganov-Luke Effect, the thermal signal of particle interactions in a semiconductor absorber operated at cryogenic temperatures, can be amplified by drifting the photogenerated electrons and holes in an electric field. This technology is not used in current experiments, in particular because of a reduction of the signal amplitude with time which is due to trapping of the charges within the absorber. We present here the first results of a novel type of Neganov-Luke Effect detector with an electric field configuration designed to improve the charge collection within the semiconductor.Comment: 6 pages, 5 figures, submitted to Journal of Low Temperature Physic

    On the Quantitative Impact of the Schechter-Valle Theorem

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    We evaluate the Schechter-Valle (Black Box) theorem quantitatively by considering the most general Lorentz invariant Lagrangian consisting of point-like operators for neutrinoless double beta decay. It is well known that the Black Box operators induce Majorana neutrino masses at four-loop level. This warrants the statement that an observation of neutrinoless double beta decay guarantees the Majorana nature of neutrinos. We calculate these radiatively generated masses and find that they are many orders of magnitude smaller than the observed neutrino masses and splittings. Thus, some lepton number violating New Physics (which may at tree-level not be related to neutrino masses) may induce Black Box operators which can explain an observed rate of neutrinoless double beta decay. Although these operators guarantee finite Majorana neutrino masses, the smallness of the Black Box contributions implies that other neutrino mass terms (Dirac or Majorana) must exist. If neutrino masses have a significant Majorana contribution then this will become the dominant part of the Black Box operator. However, neutrinos might also be predominantly Dirac particles, while other lepton number violating New Physics dominates neutrinoless double beta decay. Translating an observed rate of neutrinoless double beta decay into neutrino masses would then be completely misleading. Although the principal statement of the Schechter-Valle theorem remains valid, we conclude that the Black Box diagram itself generates radiatively only mass terms which are many orders of magnitude too small to explain neutrino masses. Therefore, other operators must give the leading contributions to neutrino masses, which could be of Dirac or Majorana nature.Comment: 18 pages, 4 figures; v2: minor corrections, reference added, matches journal version; v3: typo corrected, physics result and conclusions unchange

    Characterization of ZnSe scintillating bolometers for Double Beta Decay

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    ZnSe scintillating bolometers are good candidates for future Double Beta Decay searches, because of the 82Se high Q-value and thanks to the possibility of alpha background rejection on the basis of the scintillation signal. In this paper we report the characteristics and the anomalies observed in an extensive study of these devices. Among them, an unexpected high emission from alpha particles, accompanied with an unusual pattern of the light vs. heat scatter plot. The perspectives for the application of this kind of detectors to search for the Neutrinoless Double Beta Decay of 82Se are presented.Comment: 12 pages, 10 figure

    Measuring social-emotional development in middle childhood: the Middle Years Development Instrument

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    This paper discusses the conceptualization, development, validation, and application of the Middle Years Development Instrument (MDI) – a population-based child self-report tool that assesses children\u27s social-emotional development and well-being in the context of their home, school, and neighborhood. The MDI is administered at a population-level to 4th and 7th grade students within participating public school districts across British Columbia, Canada. Children respond to items in five domains: (1) social-emotional development, (2) connectedness to peers and adults, (3) school experiences, (4) physical health and well-being, and (5) constructive use of after-school time. Results are aggregated for schools and communities and reported back in comprehensive reports and community maps to inform planning and decision making at local and regional levels. Shared testimonials exemplify how MDI results have been used by educators, community organizers, and city planners as a catalyst for promoting children\u27s social and emotional competence and facilitating collaboration between schools and communities

    Precision Neutrino Oscillation Physics with an Intermediate Baseline Reactor Neutrino Experiment

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    We discuss the physics potential of intermediate L20÷30L \sim 20 \div 30 km baseline experiments at reactor facilities, assuming that the solar neutrino oscillation parameters Δm2\Delta m^2_{\odot} and θ\theta_{\odot} lie in the high-LMA solution region. We show that such an intermediate baseline reactor experiment can determine both Δm2\Delta m^2_{\odot} and θ\theta_{\odot} with a remarkably high precision. We perform also a detailed study of the sensitivity of the indicated experiment to Δmatm2\Delta m^2_{\rm atm}, which drives the dominant atmospheric νμ\nu_{\mu} (νˉμ\bar{\nu}_{\mu}) oscillations, and to θ\theta - the neutrino mixing angle limited by the data from the CHOOZ and Palo Verde experiments. We find that this experiment can improve the bounds on sin2θ\sin^2\theta. If the value of sin2θ\sin^2\theta is large enough, \sin^2\theta \gtap 0.02, the energy resolution of the detector is sufficiently good and if the statistics is relatively high, it can determine with extremely high precision the value of Δmatm2\Delta m^2_{\rm atm}. We also explore the potential of the intermediate baseline reactor neutrino experiment for determining the type of the neutrino mass spectrum, which can be with normal or inverted hierarchy. We show that the conditions under which the type of neutrino mass hierarchy can be determined are quite challenging, but are within the reach of the experiment under discussion.Comment: 25 page

    The Main Results of the Borexino Experiment

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    The main physical results on the registration of solar neutrinos and the search for rare processes obtained by the Borexino collaboration to date are presented.Comment: 8 pages, 8 figgures, To be published as Proceedings of the Third Annual Large Hadron Collider Physics Conference, St. Petersburg, Russia, 201

    Reactor Neutrino Experiments Compared to Superbeams

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    We present a detailed quantitative discussion of the measurement of the leptonic mixing angle sin22θ13\sin^2 2 \theta_{13} with a future reactor neutrino oscillation experiment consisting of a near and far detector. We perform a thorough analysis of the impact of various systematical errors and compare the resulting physics potential to the one of planned first-generation superbeam experiments. Furthermore, we investigate the complementarity of both types of experiments. We find that, under realistic assumptions, a determination of sin22θ13\sin^2 2 \theta_{13} down to 10210^{-2} is possible with reactor experiments. They are thus highly competitive to first-generation superbeams and may be able to test sin22θ13\sin^2 2 \theta_{13} on shorter timescales. In addition, we find that the combination of a KamLAND-size reactor experiment with one or two superbeams could substantially improve the ability to access the neutrino mass hierarchy or the leptonic CP phase.Comment: Typo in Eq. (9) corrected. 36 pages, 12 figure

    Associations between school readiness and student wellbeing: a six-year follow up study

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    Published online: 06 August 2020It is well established that children’s school readiness is associated with their later academic achievement, but less is known about whether school readiness is also associated with other measures of school success, such as students’ social and emotional wellbeing. While some previous research has shown a link between early social and emotional development and student wellbeing, results are mixed and the strength of these relationships vary depending on whether data is based on child, teachers or parents ratings and which specific student wellbeing outcomes are measured. The present study explored the association between teacher-rated school readiness (Mage = 5.6 years) across five developmental domains (physical, social, emotional, language and cognitive, and communication and general knowledge) and four aspects of student wellbeing (life satisfaction, optimism, sadness and worries) in Grade 6 (Mage = 11.9 years) in a sample of 3906 Australian children. After adjustment for background child and family-level factors, children’s early physical, social and emotional development were associated with all four wellbeing outcomes in Grade 6, but early language and cognitive skills and communication and general knowledge skills were only associated with internalising behaviours (sadness and worries). Mechanisms through which these different aspects of development might influence later wellbeing are discussed, as well as ways that schools and governments can support students’ social and emotional wellbeing.T. Gregory, E. Dal Grande, M. Brushe, D. Engelhardt, S. Luddy and M. Guhn ... et al

    New limits on heavy sterile neutrino mixing in 8B{^{8}\rm{B}}-decay obtained with the Borexino detector

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    If heavy neutrinos with mass mνHm_{\nu_{H}}\geq2me m_e are produced in the Sun via the decay 8B8Be+e++νH{^8\rm{B}} \rightarrow {^8\rm{Be}} + e^+ + \nu_H in a side branch of pp-chain, they would undergo the observable decay into an electron, a positron and a light neutrino νHνL+e++e\nu_{H}\rightarrow\nu_{L}+e^++e^-. In the present work Borexino data are used to set a bound on the existence of such decays. We constrain the mixing of a heavy neutrino with mass 1.5 MeV mνH\leq m_{\nu_{H}} \le 14 MeV to be UeH2(1034×106)|U_{eH}|^2\leq (10^{-3}-4\times10^{-6}) respectively. These are tighter limits on the mixing parameters than obtained in previous experiments at nuclear reactors and accelerators.Comment: 7 pages, 6 figure
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