The pi N N N - N N N problem. Connectedness, transition amplitudes and quasiparticle approximation

Jun, 1997
28 pages
Published in:
  • Phys.Rev.C 56 (1997) 689-701
e-Print:
Report number:
  • DFPD-97-TH-17

Citations per year

199819992000200110
Abstract:
In this paper we review the present status of the piNNN--NNN problem. In particular, we re-consider the chain-labelled approach recently proposed by us, and identify a class of graphs, previously overlooked, which prevents the kernel of the corresponding piNNN--NNN equations from being connected. We propose some pproximate schemes, yielding connected-kernel equations. A generalization of the residue method allows to relate the transition amplitudes for the coupled piNNN--NNN system to the chain-labelled formalism. The quasi-particle approach is extended to the present situation, where emission/absorption of particles is allowed. The open problems for the piNNN--NNN system in the light of the present and of previous approaches are finally discussed.
  • nuclear physics
  • many-body problem: (3nucleon pi)
  • Feynman graph
  • scattering amplitude: transition
  • approximation: pseudoparticle
  • Lippmann-Schwinger equation: coupled channel
  • integral equations
  • quantum mechanics: wave function
  • pi nucleus: nuclear reaction
  • tritium
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