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Report number	arXiv:1605.07217 ; CERN-TH-2016-123
Title	Cross-section fluctuations in chaotic scattering systems
Related title	Cross-Section Fluctuations in Chaotic Scattering Systems Cross-section fluctuations in chaotic scattering systems
Author(s)	Ericson, Torleif E. O. (CERN) ; Dietz, Barbara (Darmstadt, Tech. Hochsch.) ; Richter, Achim (Darmstadt, Tech. Hochsch. ; Warsaw, CFT)
Publication	2016-09-30
Imprint	2016-05-23
Number of pages	20
In:	Phys. Rev. E 94 (2016) 042207
DOI	10.1103/PhysRevE.94.042207
Subject category	nlin.CD ; Physics in General ; Physics in General
Abstract	Exact analytical expressions for the cross-section correlation functions of chaotic scattering sys- tems have hitherto been derived only under special conditions. The objective of the present article is to provide expressions that are applicable beyond these restrictions. The derivation is based on a statistical model of Breit-Wigner type for chaotic scattering amplitudes which has been shown to describe the exact analytical results for the scattering (S)-matrix correlation functions accurately. Our results are given in the energy and in the time representations and apply in the whole range from isolated to overlapping resonances. The S-matrix contributions to the cross-section correla- tions are obtained in terms of explicit irreducible and reducible correlation functions. Consequently, the model can be used for a detailed exploration of the key features of the cross-section correlations and the underlying physical mechanisms. In the region of isolated resonances, the cross-section correlations contain a dominant contribution from the self-correlation term. For narrow states the self-correlations originate predominantly from widely spaced states with exceptionally large partial width. In the asymptotic region of well-overlapping resonances, the cross-section autocorrelation functions are given in terms of the S-matrix autocorrelation functions. For inelastic correlations, in particular, the Ericson fluctuations rapidly dominate in that region. Agreement with known analytical and with experimental results is excellent.
Copyright/License	arXiv nonexclusive-distrib. 1.0

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