1. Light charged particles as gateway to hyperdeformation
- Author
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Herskind, B., Hagbmann, G. B., Døssing, Th, Rønn Hansen, C., Schunck, N., Sletten, G., Ødegard, S., Hübel, H., Bringel, P., Bürger, A., Neusser, A., Singh, A. K., Al-Khatib, A., Patel, S. B., Nyakó, B. M., Algora, A., Dombrádi, Z., Gál, J., Kalinka, G., Sohler, D., Molnár, J., Timár, J., Zolnai, L., Juhász, K., Bracco, A., Leon, S., Camera, F., Benzoni, G., Mason, P., Paleni, A., Million, B., Wieland, O., Bednarczyk, P., Azaiez, F., Byrski, Th, Curien, D., Dakov, O., Duchene, G., Khalfallah, F., Gall, B., Piqeras, L., Robin, J., Dudek, J., Rowley, N., Redon, N., Hannachi, F., Scheurer, J. N., Wilson, J. N., Lopez-Martens, A., Korichi, A., Hauschild, K., Roccaz, J., Siem, S., Fallon, P., Lee, I. Y., Gorgen, A., Adam Maj, Kmiecik, M., Brekiesz, M., Styczen, J., Zuber, K., Lisle, J. C., Cederwall, B., Lagergren, K., Evans, A. O., Rainovski, G., Angelis, G., La Rana, G., Moro, R., Lieder, R. M., Lieder, E. O., Gast, W., Jäger, H., Pasternak, A. A., Petrache, C. M., Petrache, D., Département Recherches Subatomiques (DRS-IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), 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 Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and 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)
- Subjects
21.60.--n, 21.10.Re, 27.60.+j ,Physical Sciences ,Settore FIS/01 - Fisica Sperimentale ,Nuclear Theory ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,Nuclear Experiment ,Nuclear & Particles Physics ,Mathematical Sciences ,Settore FIS/04 - Fisica Nucleare e Subnucleare - Abstract
International audience; The Euroball-IV \gamma -detector array, equipped with the ancillary charged particle detector array DIAMANT was used to study the residues of the fusion reaction $^{64}$Ni + $^{64}$Ni \Rightarrow $^{128}$Ba at E_{beam} = 255 and 261 MeV, in an attempt to reach the highest angular momentum and verify the existence of predicted hyperdeformed rotational bands. No discrete hyperdeformed bands were identified, but nevertheless a breakthrough was obtained through a systematic search for rotational ridge structures with very large moments of inertia J(2) \ge 100 {\mathchar h}^2 MeV^(-1), in agreement with theoretical predictions for hyperdeformed shapes. Evidence for hyperdeformation was obtained by charged particle + \gamma -ray gating, selecting triple correlated ridge structures in the continuum of each of the nuclei, $^ {118}$Te, $^{124}$Xe and $^{124,125}$Cs. In 7 additional nuclei, rotational ridges were also identified with J(2) = 71--77 {\mathchar h}^2 MeV^(-1), which most probably correspond to superdeformed shape. The angular distributions of the emitted charged particles show an excess in forward direction over expectations from pure compound evaporation, which may indicate that in-complete fusion plays an important role in the population of very elongated shapes.