3,192 research outputs found

    Required precision of mass and half-life measurements for r-process nuclei planned at future RI-beam facilities

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    In order to understand the r-process nucleosynthesis, we suggest precision required for mass and beta-decay half-life measurements planned at future RI-beam facilities. To satisfy a simple requirement that we put on nuclear model predictions, it is concluded that the detectors for the mass measurements must have a precision of 1sigma ~< 250 keV, and that the detectors for the half-life measurements demand a precision of 1sigma ~< 0.15 ms. Both the above precisions are required at the neutron richness of A/Z = 3.0 at the N=82 shell closure and A/Z = 2.9 at the N=50 shell closure. For the doubly magic nuclide 78Ni, a precision of 1sigma ~< 300 keV and 1sigma ~< 5 ms are required, respectively, for mass and half-life measurements. This analysis aims to provide a first rough guide for ongoing detector developments.Comment: 8 pages, 2 figures. in Proceedings of Int. conf. The Future Astronuclear Physics, From microscopic puzzles to macroscopic nightmares, Eds. H.M.J. Boffin et al., EAS Publication Series, EDP Sciences, in press (2004

    Strangeness Enhancement in p+p, p+Pb and Pb+Pb Collisions at LHC Energies

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    We investigate whether the quark gluon plasma (QGP) is created in small colliding systems from analyses of various hadron yields and their ratios in proton-proton (p+p), proton-lead (p+Pb) and lead-lead (Pb+Pb) collisions at LHC energies. Recently, the ALICE Collaboration reports enhancement of yield ratio of multi-strange hadrons to charged pions as a function of multiplicity at mid-rapidity. Motivated by these results, we develop the dynamical core-corona initialization framework and find that our results describe tendencies of the ALICE data especially for multi-strange hadrons. These results indicate that the QGP is partly formed in high multiplicity events in small colliding systems.Comment: 4 pages, 5 figures; contribution to the proceedings of the 8th International Conference on Quarks and Nuclear Physics (QNP2018), Tsukuba, November 13-17, 201

    Intrinsic electric field effects on few-particle interactions in coupled GaN quantum dots

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    We study the multi-exciton optical spectrum of vertically coupled GaN/AlN quantum dots with a realistic three-dimensional direct-diagonalization approach for the description of few-particle Coulomb-correlated states. We present a detailed analysis of the fundamental properties of few-particle/exciton interactions peculiar of nitride materials. The giant intrinsic electric fields and the high electron/hole effective masses give rise to different effects compared to GaAs-based quantum dots: intrinsic exciton-exciton coupling, non-molecular character of coupled dot exciton wavefunction, strong dependence of the oscillator strength on the dot height, large ground state energy shift for dots separated by different barriers. Some of these effects make GaN/AlN quantum dots interesting candidates in quantum information processing.Comment: 23 pages, 8 figures, 1 tabl

    Kaehler Manifolds of Quasi-Constant Holomorphic Sectional Curvatures

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    The Kaehler manifolds of quasi-constant holomorphic sectional curvatures are introduced as Kaehler manifolds with complex distribution of codimension two, whose holomorphic sectional curvature only depends on the corresponding point and the geometric angle, associated with the section. A curvature identity characterizing such manifolds is found. The biconformal group of transformations whose elements transform Kaehler metrics into Kaehler ones is introduced and biconformal tensor invariants are obtained. This makes it possible to classify the manifolds under consideration locally. The class of locally biconformal flat Kaehler metrics is shown to be exactly the class of Kaehler metrics whose potential function is only a function of the distance from the origin in complex Euclidean space. Finally we show that any rotational even dimensional hypersurface carries locally a natural Kaehler structure, which is of quasi-constant holomorphic sectional curvatures.Comment: 36 page

    SUGGESTION TO ROWERS OBTAINED BY INVERSE DYNAMICS AND FUZZY MODELING

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    The aims of this study were to clarify the relationships between rower’s partial motions and the rowing performance, i.e. boat speed and efficiency, and to suggest the rower which part of the body he/she should concentrate on. Inverse dynamics found time-series patterns of joint torque power. The power patterns were parameterized to six parameters, amounts and timings of three partial motions, i.e. leg extension, trunk swing and arm pull, during the driving phase of rowing stroke. These parameters are easy for a rower to sense and control one by one. Fuzzy modeling identified the relationship between the parameters and the performance. The obtained linguistic fuzzy rules gave effective suggestion to each rower

    Modern and geohistorical tsunamiites

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    17th International Sedimentological Congress [ISC 2006 FUKUOKA, JAPAN] 25-27 August, 2006FE-A8: Modern and geohistorical tsunamiites in central Japan Field Excursion Guideboo

    The origin of short-lived radionuclides and the astrophysical environment of solar system formation

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    Based on early solar system abundances of short-lived radionuclides (SRs), such as 26^{26}Al (T1/2=0.74_{1/2} = 0.74 Myr) and 60^{60}Fe (T1/2=1.5_{1/2} = 1.5 Myr), it is often asserted that the Sun was born in a large stellar cluster, where a massive star contaminated the protoplanetary disk with freshly nucleosynthesized isotopes from its supernova (SN) explosion. To account for the inferred initial solar system abundances of short-lived radionuclides, this supernova had to be close (∌\sim 0.3 pc) to the young (â©œ\leqslant 1 Myr) protoplanetary disk. Here we show that massive star evolution timescales are too long, compared to typical timescales of star formation in embedded clusters, for them to explode as supernovae within the lifetimes of nearby disks. This is especially true in an Orion Nebular Cluster (ONC)-type of setting, where the most massive star will explode as a supernova ∌\sim 5 Myr after the onset of star formation, when nearby disks will have already suffered substantial photoevaporation and/or formed large planetesimals. We quantify the probability for {\it any} protoplanetary disk to receive SRs from a nearby supernova at the level observed in the early solar system. Key constraints on our estimate are: (1) SRs have to be injected into a newly formed (â©œ\leqslant 1 Myr) disk, (2) the disk has to survive UV photoevaporation, and (3) the protoplanetary disk must be situated in an enrichment zone permitting SR injection at the solar system level without disk disruption. The probability of protoplanetary disk contamination by a supernova ejecta is, in the most favorable case, 3 ×\times 10−3^{-3}
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