Freiburg 1999 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 31: Postersitzung / Theorie
HK 31.10: Poster
Mittwoch, 24. März 1999, 10:15–12:00, Foyer
The 4 ℏ ω isoscalar monopole giant resonance in 208Pb and resonance trapping — •S.E. Muraviev1,2, I. Rotter2,3, S. Shlomo4, and M.H. Urin1 — 1Moscow Engineering Physics Institute, 115409 Moscow, Russia — 2Max-Planck-Institut für Physik komplexer Systeme, 01187 Dresden — 3Technische Universität, Institut für Theoretische Physik, 01062 Dresden — 4Cyclotron Institute, Texas A & M University, College Station, TX 77840, USA
The nuclear states at high excitation energy are embedded in the continuum and have a finite lifetime. This important fact has to be taken into account in the theoretical description of giant resonances in order to obtain an adequate description of the reaction and to study the internal properties of the system which are influenced by the continuum. If the ratio between external and internal mixing of the basis states is large, some narrow resonances may appear near the maximum of the giant resonance which carry a considerable amount of transition strength [1].
In the framework of the random phase approximation in the continuum we calculate the strength function of the 4 ℏ ω isoscalar monopole giant resonance in 208Pb. The one-particle continuum plays an important role in the formation of the structure of the strength function. Most interesting is the appearance of some narrow resonances at large excitation energy. We discuss the results obtained from the point of view of resonance trapping which is known to appear due to the strong coupling of the resonance states via the continuum. Further, we discuss the possibility of studying experimentally the structure of the giant resonance considered in this paper.
[1] V. V. Sokolov, I. Rotter, D. V. Savin, and M. Müller, Phys. Rev. C 56, 1031 and 1044 (1997)