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Title: Microscopic calculations of double and triple giant resonance excitations in heavy ion collisions

Abstract

We perform microscopic calculations of the inelastic cross sections for the double and triple excitation of giant resonances induced by heavy-ion probes within a semiclassical coupled-channels formalism. The channels are defined as eigenstates of a bosonic quartic Hamiltonian constructed in terms of collective random-phase approximation phonons. Therefore, they are superpositions of several multiphonon states, also with different numbers of phonons, and the spectrum is anharmonic. The inclusion of (n+1) phonon configurations affects the states whose main component is a n-phonon one and leads to an appreacible lowering of their energies. We check the effects of such further anharmonicities on the previously published results for the cross section for the double excitation of giant resonances (GR). We find that the only effect is a shift of the peaks toward lower energies, the double GR cross section being unmodified by the explicity inclusion of the three-phonon channels in the dynamical calculations. The latter provide an important contribution to the cross section in the triple GR energy region, which, however, is still smaller than the experimental available data. The inclusion of four-phonon configurations in the structure calculations does not modify the results.

Authors:
; ; ; ; ;  [1];  [2];  [3];  [4];  [4]
  1. I.N.F.N.-Catania and Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 67, I-95123 Catania (Italy)
  2. (Spain)
  3. (DSM-CEA/IN2P3-CNRS), B.P. 55027, F-14076 Caen Cedex 5 (France)
  4. (France)
Publication Date:
OSTI Identifier:
20864219
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 74; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevC.74.064614; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; COLLECTIVE MODEL; COUPLED CHANNEL THEORY; CROSS SECTIONS; EIGENSTATES; EXCITATION; GIANT RESONANCE; HAMILTONIANS; HEAVY ION REACTIONS; PHONONS; RANDOM PHASE APPROXIMATION; SEMICLASSICAL APPROXIMATION; VIBRATIONAL STATES

Citation Formats

Lanza, E. G., Catara, F., Andres, M. V., Chomaz, Ph., Fallot, M., Scarpaci, J. A., Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, Apdo 1065, E-41080 Sevilla, GANIL, Subatech, 4 rue Alfred Kastler BP 20722, F-44307 Nantes Cedex 3, and Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay Cedex. Microscopic calculations of double and triple giant resonance excitations in heavy ion collisions. United States: N. p., 2006. Web. doi:10.1103/PHYSREVC.74.064614.
Lanza, E. G., Catara, F., Andres, M. V., Chomaz, Ph., Fallot, M., Scarpaci, J. A., Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, Apdo 1065, E-41080 Sevilla, GANIL, Subatech, 4 rue Alfred Kastler BP 20722, F-44307 Nantes Cedex 3, & Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay Cedex. Microscopic calculations of double and triple giant resonance excitations in heavy ion collisions. United States. doi:10.1103/PHYSREVC.74.064614.
Lanza, E. G., Catara, F., Andres, M. V., Chomaz, Ph., Fallot, M., Scarpaci, J. A., Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, Apdo 1065, E-41080 Sevilla, GANIL, Subatech, 4 rue Alfred Kastler BP 20722, F-44307 Nantes Cedex 3, and Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay Cedex. Fri . "Microscopic calculations of double and triple giant resonance excitations in heavy ion collisions". United States. doi:10.1103/PHYSREVC.74.064614.
@article{osti_20864219,
title = {Microscopic calculations of double and triple giant resonance excitations in heavy ion collisions},
author = {Lanza, E. G. and Catara, F. and Andres, M. V. and Chomaz, Ph. and Fallot, M. and Scarpaci, J. A. and Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, Apdo 1065, E-41080 Sevilla and GANIL and Subatech, 4 rue Alfred Kastler BP 20722, F-44307 Nantes Cedex 3 and Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay Cedex},
abstractNote = {We perform microscopic calculations of the inelastic cross sections for the double and triple excitation of giant resonances induced by heavy-ion probes within a semiclassical coupled-channels formalism. The channels are defined as eigenstates of a bosonic quartic Hamiltonian constructed in terms of collective random-phase approximation phonons. Therefore, they are superpositions of several multiphonon states, also with different numbers of phonons, and the spectrum is anharmonic. The inclusion of (n+1) phonon configurations affects the states whose main component is a n-phonon one and leads to an appreacible lowering of their energies. We check the effects of such further anharmonicities on the previously published results for the cross section for the double excitation of giant resonances (GR). We find that the only effect is a shift of the peaks toward lower energies, the double GR cross section being unmodified by the explicity inclusion of the three-phonon channels in the dynamical calculations. The latter provide an important contribution to the cross section in the triple GR energy region, which, however, is still smaller than the experimental available data. The inclusion of four-phonon configurations in the structure calculations does not modify the results.},
doi = {10.1103/PHYSREVC.74.064614},
journal = {Physical Review. C, Nuclear Physics},
number = 6,
volume = 74,
place = {United States},
year = {Fri Dec 15 00:00:00 EST 2006},
month = {Fri Dec 15 00:00:00 EST 2006}
}
  • We investigate the consequences of anharmonic terms in the vibrational spectrum of giant dipole resonances for the double Coulomb excitation of such modes in relativistic heavy-ion collisions. It is found that apparent discrepancies between the results of two separate experiments can be put in harmony assuming minor departures from the harmonic limit because of the special features of the reaction mechanism. {copyright} {ital 1997} {ital The American Physical Society}
  • A Comment on the Letter by Morsch {ital et} {ital al}., Phys. Rev. Lett. 64, 1999 (1990).
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