38 research outputs found

    Population of 13Be in a Nucleon Exchange Reaction

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    The neutron-unbound nucleus 13Be was populated with a nucleon-exchange reaction from a 71 MeV/u secondary 13B beam. The decay energy spectrum was reconstructed using invariant mass spectroscopy based on 12Be fragments in coincidence with neutrons. The data could be described with an s-wave resonance at E = 0.73(9) MeV with a width of Gamma = 1.98(34) MeV and a d-wave resonance at E = 2.56(13) MeV with a width of Gamma = 2.29(73) MeV. The observed spectral shape is consistent with previous one-proton removal reaction measurements from 14B.Comment: Published in Phys. Rev.

    Further Insights into the Reaction Be14(CH2,X)10He

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    A previously published measurement of the reaction of a 59 MeV/nucleon 14Be beam on a deuterated polyethylene target was further analyzed to search for 12He as well as initial state effects in the population of the 10He ground state. No evidence for either was found. A lower limit of about 1 MeV was determined for a possible resonance in 12He. In addition, the three-body decay energy spectrum of 10He could not be described by a reaction mechanism calculation based on the halo structure of the initial 14Be assuming a direct α-particle removal reaction

    Evolution of the nuclear spin-orbit splitting explored via the <sup>32</sup>Si<i>(d,p)</i><sup>33</sup>Si reaction using SOLARIS

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    The spin-orbit splitting between neutron 1p orbitals at 33Si has been deduced using the single-neutron-adding (d,p) reaction in inverse kinematics with a beam of 32Si, a long-lived radioisotope. Reaction products were analyzed by the newly implemented SOLARIS spectrometer at the reaccelerated-beam facility at the National Superconducting Cyclotron Laboratory. The measurements show reasonable agreement with shell-model calculations that incorporate modern cross-shell interactions, but they contradict the prediction of proton density depletion based on relativistic mean-field theory. The evolution of the neutron 1p-shell orbitals is systematically studied using the present and existing data in the isotonic chains of = 17, 19, and 21. In each case, a smooth decrease in the separation of the - orbitals is seen as the respective p-orbitals approach zero binding, suggesting that the finite nuclear potential strongly influences the evolution of nuclear structure in this region

    First inverse kinematics measurement of key resonances in the 22Ne(p, γ)23Na reaction at stellar temperatures

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    In this Letter we report on the first inverse kinematics measurement of key resonances in the 22Ne(p,γ)23Na{}^{22}\text{Ne}(p,\gamma)^{23}\text{Na} reaction which forms part of the NeNa cycle, and is relevant for 23{}^{23}Na synthesis in asymptotic giant branch (AGB) stars. An anti-correlation in O and Na abundances is seen across all well-studied globular clusters (GC), however, reaction-rate uncertainties limit the precision as to which stellar evolution models can reproduce the observed isotopic abundance patterns. Given the importance of GC observations in testing stellar evolution models and their dependence on NeNa reaction rates, it is critical that the nuclear physics uncertainties on the origin of 23{}^{23}Na be addressed. We present results of direct strengths measurements of four key resonances in 22Ne(p,γ)23Na{}^{22}\text{Ne}(p,\gamma)^{23}\text{Na} at Ec.m._{{\text c.m.}} = 149 keV, 181 keV, 248 keV and 458 keV. The strength of the important Ec.m._{{\text c.m.}} = 458 keV reference resonance has been determined independently of other resonance strengths for the first time with an associated strength of ωγ\omega\gamma = 0.439(22) eV and with higher precision than previously reported. Our result deviates from the two most recently published results obtained from normal kinematics measurements performed by the LENA and LUNA collaborations but is in agreement with earlier measurements. The impact of our rate on the Na-pocket formation in AGB stars and its relation to the O-Na anti-correlation was assessed via network calculations. Further, the effect on isotopic abundances in CO and ONe novae ejecta with respect to pre-solar grains was investigated

    Factors shaping prayer frequency among 9- to 11-year-olds

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    This paper begins by reviewing the evidence from international research concerning the personal and social correlates of prayer frequency during childhood and adolescence. Overall these data continue to support the view that young people who pray not only report higher levels of personal wellbeing but also report higher levels of pro-social attitudes. These findings raise a research question of particular relevance within church schools regarding the factors that predict higher levels of prayer activity among students. The Student Voice Project offers data that can illuminate this research question. Among the 3,101 9- to 11-year old students who participated in the project 11% prayed daily, 9% at least once a week, 32% sometimes, 11% once or twice a year, and 37% never. The present paper tests the power of four sets of predictor variables to account for individual differences in prayer frequency among these students: personal factors (age and sex), psychological factors (using the three dimensional model of personality proposed by Eysenck), church attendance (self, mother, and father), and family discussion about prayer (mother, father, and grandparents). Multiple regression analyses identified the discussion of prayer with the mother as the single most important predictor. These findings locate the development of the practice of prayer within the home, even more than within the church

    Implicit Quantile Networks For Emulation in Jet Physics

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    The ability to model and sample from conditional densities is important in many physics applications. Implicit quantile networks (IQN) have been successfully applied to this task in domains outside physics. In this work, we illustrate the potential of IQNs as components of emulators using the simulation of jets as an example. Specifically, we use an IQN to map jets described by their 4-momenta at the generation level to jets at the event reconstruction level. The conditional densities emulated by our model closely match those generated by Delphes\texttt{Delphes}, while also enabling faster jet simulation

    Immersive full-surround multi-user system design

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    This paper describes our research in full-surround, multimodal, multi-user, immersive instrument design in a large VR instrument. The three-story instrument, designed for large-scale, multimodal representation of complex and potentially high-dimensional information, specifically focuses on multi-user participation by facilitating interdisciplinary teams of co-located researchers in exploring complex information through interactive visual and aural displays in a full-surround, immersive environment. We recently achieved several milestones in the instrument's design that improves multi-user participation when exploring complex data representations and scientific simulations. These milestones include affordances for "ensemble-style" interaction allowing groups of participants to see, hear, and explore data as a team using our multi-user tracking and interaction systems; separate visual display modes for rectangular legacy content and for seamless surround-view stereoscopic projection using 4 high-resolution, high-lumen projectors with hardware warping and blending integrated with 22 small-footprint projectors placed above and below the instrument's walkway; and a 3D spatial audio system enabling a variety of sound spatialization techniques. These facilities can be accessed and controlled by a multimodal framework for authoring applications integrating visual, audio, and interactive elements. We report on the achieved instrument design. © 2014 Elsevier Ltd. All rights reserved
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