Unstable particles in s-matrix theory

Daniel Zwanziger

    Research output: Contribution to journalArticle

    Abstract

    The consequences of the existence of complex poles in scattering amplitudes, corresponding to resonances or unstable particles, are investigated. Specific examples show that corresponding to such poles are normal threshold cuts lying near the physical region and which cause "wooly cusps" in scattering cross sections. The discontinuity across such a cut is expressed by a unitarity-like relation in terms of unphysical amplitudes with unstable external particles defined by the residues of the complex poles. More generally, it is shown that the Landau equations for the singularities must be extended to include all unstable as well as stable particles. The Cutkosky formulas specify the corresponding discontinuities in terms of the physical and unphysical amplitudes.

    Original languageEnglish (US)
    Pages (from-to)888-898
    Number of pages11
    JournalPhysical Review
    Volume131
    Issue number2
    DOIs
    StatePublished - 1963

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    matrix theory
    poles
    discontinuity
    cusps
    scattering amplitude
    scattering cross sections
    thresholds
    causes

    ASJC Scopus subject areas

    • Physics and Astronomy(all)

    Cite this

    Unstable particles in s-matrix theory. / Zwanziger, Daniel.

    In: Physical Review, Vol. 131, No. 2, 1963, p. 888-898.

    Research output: Contribution to journalArticle

    Zwanziger, Daniel. / Unstable particles in s-matrix theory. In: Physical Review. 1963 ; Vol. 131, No. 2. pp. 888-898.
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