Observation of double isovector giant dipole resonances from pion double charge exchange

S. Mordechai, H. T. Fortune, J. M. Odonnell, G. Liu, M. Burlein, A. H. Wuosmaa, S. Greene, C. L. Morris, N. Auerbach, S. H. Yoo, C. Fred Moore

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44 Scopus citations


We report the observation of double isovector giant dipole resonances in (+,-) and, for the first time, also in (-,+) double-charge-exchange reactions at T=292 MeV. The resonances have been observed on nine targets covering a wide range of mass at Q values around -50 MeV in (+,-), but at significantly lower energy (Q=-33.8 MeV) in the inverse reaction on Fe56. The centroid energies in both reactions are very close to the energies at which the "Tz=2 double giant dipole (J=0+,2+,"T=2) states are expected to appear. Angular distributions have been measured for the (+,-) resonances on Ca40,56, Fe, and Nb93 and each is observed to have a quadrupole shape. Based on their energies, angular distributions, cross sections, and the comparison between the (+,-) and (-,+) data on Fe56, we identify the resonances as double giant dipole states (i.e. states arising from a charge-exchange dipole operator acting twice on the ground-state wave function). The data from the present and recent observations indicate that the newly discovered resonance is a general collective feature of all nuclei.

Original languageEnglish
Pages (from-to)202-212
Number of pages11
JournalPhysical Review C - Nuclear Physics
Issue number1
StatePublished - 1 Jan 1990

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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