SINGULARITIES IN THE UNPHYSICAL SHEETS AND THE ISOBAR MODEL
Scattering amplitudes involving two- and three-particle states are continued across the inelastic section of the unitarity cut, and the singularities in the unphysical sheets thus reached are determined. Associated with an unstable particle is a complex unitarity cut, through which another unphysical sheet is reached. Dynamical singularities with a Born-type diagram for the three-particle scattering amplitude are found to be present in the elastic scattering and the production amplitudes also because of the coupling by unitarity. These singularities are isolated from the physical region by the complex unitarity cut and thus cannot be directly responsible for any resonance phenomenon, However, if the interaction force is favorable, a resonance pole can occur in a different Riemann sheet in the vicinity of these singularities. This resonance pole is directly accessible from the physical region and can therefore give rise to a resonance. (auth)
- Research Organization:
- Univ. of California, Berkeley
- NSA Number:
- NSA-17-026345
- OSTI ID:
- 4694956
- Journal Information:
- Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 130; ISSN PHRVA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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