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Vitez-Sveiczer, A. et al, Algora, A., Morales, A. I., Rubio, B., Agramunt, J., Guadilla, V., et al. (2022). The beta-decay of Kr-70 into Br-70: Restoration of the pseudo-SU(4) symmetry. Phys. Lett. B, 830, 137123–8pp.
Abstract: The beta-decay of the even-even nucleus Kr-70 with Z=N+2, has been investigated at the Radioactive Ion Beam Factory (RIBF) of the RIKEN Nishina Center using the BigRIPS fragment separator, the ZeroDegree Spectrometer, the WAS3ABI implantation station and the EURICA HPGe cluster array. Fifteen gamma-rays associated with the beta-decay of( 70)Kr into Br-70 have been identified for the first time, defining ten populated states below E-exc=3300 keV. The half-life of Kr-70 was derived with increased precision and found to be t(1/2)=45.19 +/- 0.14 ms. The beta-delayed proton emission probability has also been determined as epsilon(p)=0.545(23)%. An increase in the beta-strength to the yrast 1(+) state in comparison with the heaviest Z=N+2 system studied so far (Ge-62 decay) is observed that may indicate increased np correlations in the T=0 channel. The beta-decay strength deduced from the results is interpreted in terms of the proton-neutron quasiparticle random-phase approximation (pnQRPA) and also with a schematic model that includes isoscalar and isovector pairing in addition to quadrupole deformation. The application of this last model indicates an approximate realization of pseudo-SU(4) symmetry in this system.
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Mistry, A. K. et al, Tain, J. L., Agramunt, J., Algora, A., Guadilla, V., Morales, A. I., et al. (2022). The DESPEC setup for GSI and FAIR. Nucl. Instrum. Methods Phys. Res. A, 1033, 166662–18pp.
Abstract: The DEcay SPECtroscopy (DESPEC) setup for nuclear structure investigations was developed and commissioned at GSI, Germany in preparation for a full campaign of experiments at the FRS and Super-FRS. In this paper, we report on the first employment of the setup in the hybrid configuration with the AIDA implanter coupled to the FATIMA LaBr3(Ce) fast-timing array, and high-purity germanium detectors. Initial results are shown from the first experiments carried out with the setup. An overview of the setup and function is discussed, including technical advancements along the path.
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Puppe, P., Frekers, D., Adachi, T., Akimune, H., Aoi, N., Bilgier, B., et al. (2011). High-resolution ((3)He,t) reaction on the double-beta decaying nucleus (136)Xe. Phys. Rev. C, 84(5), 051305–5pp.
Abstract: A ((3)He, t) charge-exchange reaction experiment on the double-beta decaying nucleus (136)Xe has been performed at an incident energy of 420 MeV with the objective to measure the Gamow-Teller (GT) strength distribution in (136)Cs. The measurements have been carried out at the dispersion-matched WS beam line and the Grand Raiden spectrometer of the Research Center for Nuclear Physics in Osaka, where an energy resolution of 42 keV was achieved. A new gas cell with thin windows made of polyethylene naphthalate has been employed as a target. The extracted GT strength distribution is confronted with the rather long 2 nu beta beta decay half-life of (136)Xe.
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Orrigo, S. E. A. et al, Rubio, B., Agramunt, J., Algora, A., & Molina, F. (2014). Observation of the beta-Delayed gamma-Proton Decay of Zn-56 and its Impact on the Gamow-Teller Strength Evaluation. Phys. Rev. Lett., 112(22), 222501–5pp.
Abstract: We report the observation of a very exotic decay mode at the proton drip line, the beta-delayed gamma-proton decay, clearly seen in the beta decay of the T-z = -2 nucleus Zn-56. Three gamma-proton sequences have been observed after the beta decay. Here this decay mode, already observed in the sd shell, is seen for the first time in the f p shell. Both. and proton decays have been taken into account in the estimation of the Fermi and Gamow-Teller strengths. Evidence for fragmentation of the Fermi strength due to strong isospin mixing is found.
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XENON100 Collaboration(Aprile, E. et al), & Orrigo, S. E. A. (2014). First axion results from the XENON100 experiment. Phys. Rev. D, 90(6), 062009–7pp.
Abstract: We present the first results of searches for axions and axionlike particles with the XENON100 experiment. The axion-electron coupling constant, g(Ae), has been probed by exploiting the axioelectric effect in liquid xenon. A profile likelihood analysis of 224.6 live days x 34-kg exposure has shown no evidence for a signal. By rejecting g(Ae) larger than 7.7 x 10(-12) (90% C. L.) in the solar axion search, we set the best limit to date on this coupling. In the frame of the DFSZ and KSVZ models, we exclude QCD axions heavier than 0.3 and 80 eV/c(2), respectively. For axionlike particles, under the assumption that they constitute the whole abundance of dark matter in our galaxy, we constrain gAe to be lower than 1 x 10(-12) (90% C.L.) for masses between 5 and 10 keV/c(2).
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