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HK: Physik der Hadronen und Kerne
HK 19: Nuclear Structure/Spectroscopy III
HK 19.4: Vortrag
Dienstag, 9. März 2004, 16:45–17:00, D
Fragmentation of the E1 two-phonon strengths in odd-mass nuclei near the N=82 shell closure — •M. Scheck1, H. von Garrel1, P. von Brentano2, C. Fransen2, G. Friessner2, N. Hollmann2, J. Jolie2, U. Kneissl1, C. Kohstall1, A. Linnemann2, D. Mücher2, N. Pietralla2, H.H. Pitz1, F. Stedile1, C. Stoyanov3, N. Tsoneva3,4, S. Walter1, and V. Werner2 — 1Inst. für Strahlenphysik, Universität Stuttgart — 2Inst. für Kernphysik, Universität zu Köln — 3INRNE, Sofia — 4Inst. für Theor. Physik, Universität Giessen
Quadrupole-octupole coupled two-phonon E1 excitations (2+⊗3−) represent the dominant low-lying E1 excitations in spherical even-even nuclei near shell closures [1]. In the present studies the fragmentation of the dipole strength in odd-mass nuclei near the N=82 shell closure was investigated. The recent photon scattering experiments on 135,137Ba, 139La, and 141Pr extend systematically our previous measurements on 143Nd [2]. All experiments were performed at the photon scattering facility of the 4.3 MV Stuttgart Dynamitron using bremsstrahlung beams of 4 MeV end point energy. The fragmentation and partially observed reduction of the dipole strengths as compared to those in the neighboring even-even N=82 isotones [3] arediscussed and compared with our similar results for nuclei near the Z=50 shell closure (see [4]).
[1] W. Andrejtscheff et al., Phys. Lett. B 506, 239 (2001).
[2] A. Zilges et al., Phys. Rev. Lett. 70, 2880 (1993).
[3] R.-D. Herzberg et al., Nucl. Phys. A 592, 211 (1995).
[4] J. Bryssinck et al., Phys. Rev. C 65, 024313 (2002).
Supported by DFG under contracts Kn 154/31 and Pi 393/1-2