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HK: Fachverband Physik der Hadronen und Kerne

HK 42: Hadronenstruktur und -spektroskopie VII

HK 42.2: Talk

Wednesday, March 23, 2011, 17:00–17:15, C-2

On causality, unitarity and perturbative expansions — •Igor Danilkin, Ashot Gasparyan, and Matthias Lutz — GSI, Planck Str. 1, 64291 Darmstadt, Germany

We present a pedagogical case study how to combine micro-causality and unitarity based on a perturbative approach [1]. The method we advocate constructs an analytic extrapolation of partial-wave scattering amplitudes that is constrained by the unitarity condition. Suitably constructed conformal mappings help to arrive at a systematic approximation of the scattering amplitude. The technique is illustrated at hand of a Yukawa interaction. The typical case of a superposition of strong short-range and weak long-range forces is investigated.

[1] I.V. Danilkin, A.M. Gasparyan, M.F.M. Lutz, arXiv:1009.5928