2020 Impact factor 3.043
Hadrons and Nuclei
Eur. Phys. J. A 7, 15-18

Short note

Is the 4.742 MeV state in 88Sr the 1- two-phonon state?

L. Käubler1 - H. Schnare1 - R. Schwengner1 - P. von Brentano2 - F. Dönau1 - J. Eberth2 - J. Enders3 - A. Fitzler2 - C. Fransen2 - M. Grinberg4 - E. Grosse1 - R.-D. Herzberg2 - H. Kaiser3 - P. von Neumann-Cosel3 - N. Pietralla2 - H. Prade1 - A. Richter3 - S. Skoda2 - Ch. Stoyanov4 - H.-G. Thomas2 - H. Tiesler2 - D. Weisshaar2 - I. Wiedenhöver2

1 Institut für Kern- und Hadronenphysik, Forschungszentrum Rossendorf, 01314 Dresden, Germany
2 Institut für Kernphysik der Universität zu Köln, 50937 Köln, Germany
3 Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany
4 Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria

Received: 3 November 1999 Communicated by

Abstract
A nuclear resonance fluorescence experiment on 88Sr has been performed with bremsstrahlung of 6.7 MeV endpoint energy. The $\gamma$-ray linear polarisation has been measured with a EUROBALL CLUSTER detector used as a Compton polarimeter. The results indicate positive parity for the J=1 state at 4.742 MeV in 88Sr, in contrast to the previous interpretation as a 1- two-phonon $(2^{+}_{1} \otimes 3^{-}_{1})$state and in conflict with the predictions of the quasiparticle-phonon model. On the basis of such calculations the 1+ state at 3.486 MeV may be considered as the 1+1 one-phonon state and the very strong 1 $^{+}_{1} \rightarrow$ 0+1 deexcitation as proton spin-flip 2p1/2 $\rightarrow$ 2p3/2 transition.

PACS
21.10.Hw Spin, parity, and isobaric spin - 21.10.Tg Lifetimes - 21.60.-n Nuclear-structure models and methods - 27.50.+e 59 $\leq A \leq$ 89


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