1. Multi-quasiparticle sub-nanosecond isomers in $^{178}$W
- Author
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M. Lebois, R. Shearman, M. Brunet, L. Qi, Gavin Lotay, V. Vedia, V. Sánchez-Tembleque, J.-M. Régis, M. Heine, S. Courtin, R. Canavan, Mohammad Nakhostin, Giuseppe Lorusso, D. T. Doherty, Ł. W. Iskra, J. N. Wilson, C. R. Nita, S. Bottoni, V. Karayonchev, N. Cieplicka-Oryńczak, A. R. L. Kennington, Zs. Podolyák, J. Jolie, J. Benito, P. H. Regan, P. Koseoglou, A. Blazhev, P. A. Söderström, L. M. Fraile, P. M. Walker, Stephan Oberstedt, W. Witt, K. O. Zell, N. Jovancevic, K. Hadynska-Klek, M. Rudigier, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Université Paris-Sud - Paris 11 (UP11), Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Physics ,Nuclear and High Energy Physics ,010308 nuclear & particles physics ,Detector ,Aucun ,Calorimetry ,Scintillator ,Nanosecond ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,01 natural sciences ,lcsh:QC1-999 ,3. Good health ,0103 physical sciences ,Quasiparticle ,ddc:530 ,Física nuclear ,Atomic physics ,010306 general physics ,Spectroscopy ,lcsh:Physics ,Beam (structure) ,Mixing (physics) - Abstract
We report on the first measurement of the half-lives of K-pi = 11(-) and 12(+) four-quasiparticle states in the even-even nucleus W-178. The sub-nanosecond half-lives were measured by applying the centroid shift method to data taken with LaBr3(Ce) scintillator detectors of the NuBall array at the ALTO facility in Orsay, France. The half-lives of these states only became experimentally accessible by the combination of several experimental techniques - scintillator fast timing, isomer spectroscopy with a pulsed beam, and the event-by-event calorimetry information provided by the NuBall array. The measured half-lives are 476(44)ps and 275(65)ps for the I-pi = 11(-) and 12(+) states, respectively. The decay transitions include weakly hindered E1 and E2 branches directly to the ground-state band, bypassing the two-quasiparticle states. This is the first such observation for an E1 transition. The interpretation of the small hindrance hinges on mixing between the ground-state band and the t-band. (C) 2019 The Author(s). Published by Elsevier B.V.
- Published
- 2020