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arXiv · 1009.5928

On causality, unitarity and perturbative expansions

I. V. Danilkin·A. M. Gasparyan·M. F. M. Lutz
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Abstract

We present a pedagogical case study how to combine micro-causality and unitarity based on a perturbative approach. 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.

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I. V. Danilkin, A. M. Gasparyan, M. F. M. Lutz. 2010-09-29. On causality, unitarity and perturbative expansions. https://doi.org/10.1016/j.physletb.2011.01.036

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