11 research outputs found

    Low spin spectroscopy of neutron-rich 43,44,45Cl via {\beta} and (\beta}n decay

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    {\beta} decay of neutron-rich isotopes 43,45 S,studied at the National Superconducting Cyclotron Laboratory is reported here. {\beta} delayed {\gamma} transitions were detected by an array of 16 clover detectors surrounding the Beta Counting Station which consists of a 40x40 Double Sided Silicon Strip Detector followed by a Single Sided Silicon Strip Detector. {\beta} decay half-lives have been extracted for 43,45 S by correlating implants and decays in the pixelated implant detector with further coincidence with {\gamma} transitions in the daughter nucleus. The level structure of 43,45 Cl is expanded by the addition of 20 new {\gamma} transitions in 43Cl and 8 in 45 Cl with the observation of core excited negative-parity states for the first time. For 45 S decay, a large fraction of the {\beta} decay strength goes to delayed neutron emission populating states in 44 Cl which are also presented. Comparison of experimental observations is made to detailed shell-model calculations using the SDPFSDG-MU interaction to highlight the role of the diminished N = 28 neutron shell gap and the near degeneracy of the proton s 1/2 and d 3/2 orbitals on the structure of the neutron-rich Cl isotopes. The current work also provides further support to a ground state spin-parity assignment of 3/2 + in 45 Cl

    Microsecond Isomer at the N=20 Island of Shape Inversion Observed at FRIB

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    Excited-state spectroscopy from the first Facility for Rare Isotope Beams (FRIB) experiment is reported. A 24(2)-μ\mus isomer was observed with the FRIB Decay Station initiator (FDSi) through a cascade of 224- and 401-keV γ\gamma rays in coincidence with 32Na^{32}\textrm{Na} nuclei. This is the only known microsecond isomer (1 μs≤T1/2<1 ms1{\text{ }\mu\text{s}}\leq T_{1/2} < 1\text{ ms}) in the region. This nucleus is at the heart of the N=20N=20 island of shape inversion and is at the crossroads of spherical shell-model, deformed shell-model, and ab initio theories. It can be represented as the coupling of a proton hole and neutron particle to 32Mg^{32}\textrm{Mg}, 32Mg+π−1+ν+1^{32}\textrm{Mg}+\pi^{-1} + \nu^{+1}. This odd-odd coupling and isomer formation provides a sensitive measure of the underlying shape degrees of freedom of 32Mg^{32}\textrm{Mg}, where the onset of spherical-to-deformed shape inversion begins with a low-lying deformed 2+2^+ state at 885 keV and a low-lying shape-coexisting 02+0_2^+ state at 1058 keV. We suggest two possible explanations for the 625-keV isomer in 32^{32}Na: a 6−6^- spherical shape isomer that decays by E2E2 or a 0+0^+ deformed spin isomer that decays by M2M2. The present results and calculations are most consistent with the latter, indicating that the low-lying states are dominated by deformation.Comment: 7 pages, 5 figures, accepted by Physical Review Letter

    Narcissism: a factor behind the selective sharing of news online

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    The current study examined the extent to which narcissism influences the social network users’ intention to share positive and negative life events with (close or unknown) online contacts. Using an online survey, small vignettes and a cross-sectional convenience sample of 119 participants, the results showed that narcissism positively predicted sharing intention of positive and negative life events with strangers. However, individuals rating higher in narcissism were less likely to share negative news with family. The research findings suggest that personality traits such as narcissism, the type of contacts online, and the nature of the news may shape what information is shared by online users. The type of news presented may therefore be a function of who is posting the content, their personality, and the kind of social network contacts they have online

    57^{57}Zn β\beta-delayed proton emission establishes the 56^{56}Ni rprp-process waiting point bypass

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    International audience•In our letter, we address the dominant uncertainty regarding the extent of the rp-process flow bypass around Ni56 waiting point for astrophysical conditions relevant to Type-1 X-ray bursts.•We removed the final significant uncertainty, the beta-delayed proton branching ratio for Zn57, definitively determining that there is a Ni56 bypass.•In addition, we also identified the second case of the exotic β−γ−p decay mode in the fp-shell. We measured the Zn57β-delayed proton (βp) and γ emission at the National Superconducting Cyclotron Laboratory. We find a Zn57 half-life of 43.6±0.2 ms, βp branching ratio of (84.7±1.4)%, and identify four transitions corresponding to the exotic β-γ-p decay mode, the second such identification in the fp-shell. The p/γ ratio was used to correct for isospin mixing while determining the Zn57 mass via the isobaric multiplet mass equation. Previously, it was uncertain as to whether the rp-process flow could bypass the textbook waiting point Ni56 for astrophysical conditions relevant to Type-I X-ray bursts. Our results definitively establish the existence of the Ni56 bypass, with 14-17% of the rp-process flow taking this route

    57^{57}Zn β\beta-delayed proton emission establishes the 56^{56}Ni rprp-process waiting point bypass

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    We measured the 57^{57}Zn β\beta-delayed proton (β\betap) and γ\gamma emission at the National Superconducting Cyclotron Laboratory. We find a 57^{57}Zn half-life of 43.6 ±\pm 0.2 ms, β\betap branching ratio of (84.7 ±\pm 1.4)%, and identify four transitions corresponding to the exotic β\beta-γ\gamma-pp decay mode, the second such identification in the fpf p-shell. The p/γp/\gamma ratio was used to correct for isospin mixing while determining the 57^{57}Zn mass via the isobaric multiplet mass equation. Previously, it was uncertain as to whether the rp-process flow could bypass the textbook waiting point 56^{56}Ni for astrophysical conditions relevant to Type-I X-ray bursts. Our results definitively establish the existence of the 56^{56}Ni bypass, with 14-17% of the rprp-process flow taking this route
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