12,337 research outputs found

    Neutrinoless double-beta decay matrix elements in large shell-model spaces with the generator-coordinate method

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    We use the generator-coordinate method with realistic shell-model interactions to closely approximate full shell-model calculations of the matrix elements for the neutrinoless double-beta decay of 48^{48}Ca, 76^{76}Ge, and 82^{82}Se. We work in one major shell for the first isotope, in the f5/2pg9/2f_{5/2}pg_{9/2} space for the second and third, and finally in two major shells for all three. Our coordinates include not only the usual axial deformation parameter β\beta, but also the triaxiality angle γ\gamma and neutron-proton pairing amplitudes. In the smaller model spaces our matrix elements agree well with those of full shell-model diagonalization, suggesting that our Hamiltonian-based GCM captures most of the important valence-space correlations. In two major shells, where exact diagonalization is not currently possible, our matrix elements are only slightly different from those in a single shell.Comment: 8 pages, 7 figure

    Searching for high-KK isomers in the proton-rich A80A\sim80 mass region

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    Configuration-constrained potential-energy-surface calculations have been performed to investigate the KK isomerism in the proton-rich A80A\sim80 mass region. An abundance of high-KK states are predicted. These high-KK states arise from two and four-quasi-particle excitations, with Kπ=8+K^{\pi}=8^{+} and Kπ=16+K^{\pi}=16^{+}, respectively. Their excitation energies are comparatively low, making them good candidates for long-lived isomers. Since most nuclei under studies are prolate spheroids in their ground states, the oblate shapes of the predicted high-KK states may indicate a combination of KK isomerism and shape isomerism

    Robust Adaptive Control of a Class of Nonlinear Strict-feedback Discrete-time Systems with Exact Output Tracking

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    10.1016/j.automatica.2009.07.025Automatica45112537-2545ATCA

    Database development and intranet based image included database management system for ballistic firearm identification system

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    The process of imaging, collecting and searching a cartridge case to identifying its suspected firearm is a time consuming procedure. Within this study, a cartridge case identification database management system in an Intranet environment is designed and implemented, thus enabling firearm examiners from different forensic laboratories to engage firearm identification without the constraints of time and location. Specifically, the study investigates appropriate database management system for image involved and Intranet secured ballistics firearm identification database. The results demonstrated that a computerized firearm identification system could be implemented in Intranet with a secure, scalable, performable Intranet database management system

    Observation of Landau quantization and standing waves in HfSiS

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    Recently, HfSiS was found to be a new type of Dirac semimetal with a line of Dirac nodes in the band structure. Meanwhile, Rashba-split surface states are also pronounced in this compound. Here we report a systematic study of HfSiS by scanning tunneling microscopy/spectroscopy at low temperature and high magnetic field. The Rashba-split surface states are characterized by measuring Landau quantization and standing waves, which reveal a quasi-linear dispersive band structure. First-principles calculations based on density-functional theory are conducted and compared with the experimental results. Based on these investigations, the properties of the Rashba-split surface states and their interplay with defects and collective modes are discussed.Comment: 6 pages, 5 figure

    Normal heat conduction in one dimensional momentum conserving lattices with asymmetric interactions

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    The heat conduction behavior of one dimensional momentum conserving lattice systems with asymmetric interparticle interactions is numerically investigated. It is found that with certain degree of interaction asymmetry, the heat conductivity measured in nonequilibrium stationary states converges in the thermodynamical limit, in clear contrast to the well accepted viewpoint that Fourier's law is generally violated in low dimensional momentum conserving systems. It suggests in nonequilibrium stationary states the mass gradient resulted from the asymmetric interactions may provide an additional phonon scattering mechanism other than that due to the nonlinear interactions.Comment: 4 pages, 4 figure
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