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Δ Excitations in Nuclei and the Coherent Pion Decay

  • F. Osterfeld
  • B. Körfgen
  • P. Oltmanns
  • T. Udagawa

Abstract

The Δ excitations in nuclei induced by intermediate energy charge exchange reactions are analyzed within the isobar-hole model. It is shown that the isovector spin-longitudinal () response function of nuclei in the Δ resonance region is shifted down in energy by ~ 60 MeV in comparison to the spin-transverse () response function. This shift is consistent with pion and photon total cross section data. The coherent pion decay of the Δ resonance is studied by means of the 12 C(p, nπ +)12 C(g.s.)and 12 C(γ, π 0)12 C(g.s.) coincidence reactions. The calculations show that the coherent pion production cross section provides a unique signature on the nuclear pionic mode. The coherent pions in the charge exchange reactions have a peak energy of E π = 250 MeV and a strongly forward peaked angular distribution. The coherent pions from the pion-photoproduction reaction have a peak energy of E π = 220 MeV and an angular distribution which peaks near θ π = 30°.

Keywords

Transition Density Inclusive Cross Section Residual Interaction Full Curve Spin Observable 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • F. Osterfeld
    • 1
  • B. Körfgen
    • 1
  • P. Oltmanns
    • 1
  • T. Udagawa
    • 2
  1. 1.Institut für KernphysikKFA Jülich GmbHJülichGermany
  2. 2.Department of PhysicsUniversity of TexasAustinUSA

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