489 research outputs found

    Superdeformation in Asymmetric N>>Z Nucleus 40^{40}Ar

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    A rotational band with five γ\gamma-ray transitions ranging from 2+^{+} to 12+^{+} states was identified in 40^{40}Ar. This band is linked through γ\gamma transitions from the excited 2+^{+}, 4+^{+} and 6+^{+} levels to the low-lying states; this determines the excitation energy and the spin-parity of the band. The deduced transition quadrupole moment of 1.450.31+0.49eb^{+0.49}_{-0.31} eb indicates that the band has a superdeformed shape. The nature of the band is revealed by cranked Hartree--Fock--Bogoliubov calculations and a multiparticle--multihole configuration is assigned to the band

    μ s isomers of Nd 158,160

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    The neutron-rich nuclei Nd158,160 have been studied via delayed γ-ray spectroscopy of μs isomeric states at the RIBF facility, RIKEN. These nuclei were produced following the projectile fission of a 345 AMeVU238 beam and delayed γ rays were detected by the EURICA cluster Ge array. The isomeric states have measured half-lives of 339(20) ns and 1.63(21) μs for Nd158 and Nd160, respectively. From the observed γ decays and the systematics of levels in the neighboring Nd isotopes first level schemes were constructed for these nuclei. The isomeric states of Nd158,160 have been assigned spins of (6-) and (4-), with proposed ν5/2[523] - ν7/2[633] and ν1/2[521] - ν7/2[633] configurations, respectively. © 2016 American Physical Society

    Bethe Ansatz Equations for General Orbifolds of N=4 SYM

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    We consider the Bethe Ansatz Equations for orbifolds of N =4 SYM w.r.t. an arbitrary discrete group. Techniques used for the Abelian orbifolds can be extended to the generic non-Abelian case with minor modifications. We show how to make a transition between the different notations in the quiver gauge theory.Comment: LaTeX, 66 pages, 9 eps figures, minor corrections, references adde

    Perturbative Search for Fixed Lines in Large N Gauge Theories

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    The logarithmic running of marginal double-trace operators is a general feature of 4-d field theories containing scalar fields in the adjoint or bifundamental representation. Such operators provide leading contributions in the large N limit; therefore, the leading terms in their beta functions must vanish for a theory to be large N conformal. We calculate the one-loop beta functions in orbifolds of the N=4 SYM theory by a discrete subgroup Gamma of the SU(4) R-symmetry, which are dual to string theory on AdS_5 x S^5/Gamma. We present a general strategy for determining whether there is a fixed line passing through the origin of the coupling constant space. Then we study in detail some classes of non-supersymmetric orbifold theories, and emphasize the importance of decoupling the U(1) factors. Among our examples, which include orbifolds acting freely on the S^5, we do not find any large N non-supersymmetric theories with fixed lines passing through the origin. Connection of these results with closed string tachyon condensation in AdS_5 x S^5/Gamma is discussed.Comment: 31 pages, 4 figures, latex v2: Clarifications and reference adde

    Nonlinear optical interactions in silicon waveguides

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    The strong nonlinear response of silicon photonic nanowire waveguides allows for the integration of nonlinear optical functions on a chip. However, the detrimental nonlinear optical absorption in silicon at telecom wavelengths limits the efficiency of many such experiments. In this review, several approaches are proposed and demonstrated to overcome this fundamental issue. By using the proposed methods, we demonstrate amongst others supercontinuum generation, frequency comb generation, a parametric optical amplifier, and a parametric optical oscillator

    Superdeformed bands in neutron-rich Sulfur isotopes suggested by cranked Skyrme-Hartree-Fock calculations

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    On the basis of the cranked Skyrme-Hartree-Fock calculations in the three-dimensional coordinate-mesh representation, we suggest that, in addition to the well-known candidate 32S, the neutron-rich nucleus 36S and the drip-line nuclei,48S and 50S, are also good candidates for finding superdeformed rotational bands in Sulfur isotopes. Calculated density distributions for the superdeformed states in 48S and 50S exhibit superdeformed neutron skinsComment: 18 pages including 10 ps figure

    Turbulent magnetic field in the HII region Sh 2-27

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    Magnetic fields in the turbulent interstellar medium (ISM) are a key element in understanding Galactic dynamics, but there are many observational challenges. One useful probe for studying the magnetic field component parallel to the line of sight (LoS) is Faraday rotation of linearly polarized radio synchrotron emission, combined with Hα\alpha observations. HII regions are the perfect laboratories to probe such magnetic fields as they are localized in space, and are well-defined sources often with known distances and measurable electron densities. We chose the HII region Sharpless 2-27 (Sh 2-27). By using a map of the magnetic field strength along the LoS (BB_{\parallel}) for the first time, we investigate the basic statistical properties of the turbulent magnetic field inside Sh 2-27. We study the scaling of the magnetic field fluctuations, compare it to the Kolmogorov scaling, and attempt to find an outer scale of the turbulent magnetic field fluctuations. We estimate the median value of nen_e as 7.3±0.17.3\pm0.1 cm3^{-3}, and the median value of BB_{\parallel} as 4.5±0.1-4.5\pm0.1 μ\muG, which is comparable to the magnetic field strength in diffuse ISM. The slope of the structure function of the estimated BB_{\parallel}-map is found to be slightly steeper than Kolmogorov, consistent with our Gaussian-random-field BB_{\parallel} simulations revealing that an input Kolmogorov slope in the magnetic field results in a somewhat steeper slope in BB_{\parallel}. These results suggest that the lower limit to the outer scale of turbulence is 10 pc in the HII region, which is comparable to the size of the computation domain. This may indicate that the turbulence probed here could actually be cascading from the larger scales in the ambient medium, associated with the interstellar turbulence in the general ISM, which is illuminated by the presence of Sh 2-27.Comment: 14 pages, 11 figures. Accepted by A&

    Change of nuclear configurations in the neutrinoless double-β\beta decay of 130^{130}Te \rightarrow 130^{130}Xe and 136^{136}Xe \rightarrow 136^{136}Ba

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    The change in the configuration of valence protons between the initial and final states in the neutrinoless double-β\beta decay of 130^{130}Te \rightarrow 130^{130}Xe and of 136^{136}Xe \rightarrow 136^{136}Ba has been determined by measuring the cross sections of the (dd,3^3He) reaction with 101-MeV deuterons. Together with our recent determination of the relevant neutron configurations involved in the process, a quantitative comparison with the latest shell-model and interacting-boson-model calculations reveals significant discrepancies. These are the same calculations used to determine the nuclear matrix elements governing the rate of neutrinoless double-β\beta decay in these systems.Comment: 10 pages, 4 figures, 9 table
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