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arXiv · 1003.1463

Extraction of bound-state parameters from dispersive sum rules

Wolfgang Lucha·Dmitri Melikhov·Silvano Simula
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Abstract

The procedure of extracting the ground-state parameters from vacuum-to-vacuum and vacuum-to-hadron correlators within the method of sum rules is considered. The emphasis is laid on the crucial ingredient of this method - the effective continuum threshold. A new algorithm to fix this quantity is proposed and tested. First, a quantum-mechanical potential model which provides the only possibility to probe the reliability and the actual accuracy of the sum-rule method is used as a study case. In this model, our algorithm is shown to lead to a remarkable improvement of the accuracy of the extracted ground-state parameters compared to the standard procedures adopted in the method and used in all previous applications of dispersive sum rules in QCD. As a next step, it is demonstrated that the procedures of extracting the ground-state decay constant in the potential model and in QCD are quantitatively very close to each other. Therefore, the application of the proposed algorithm in QCD promises a considerable increase of the accuracy of the extracted hadron parameters.

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Wolfgang Lucha, Dmitri Melikhov, Silvano Simula. 2010-03-07. Extraction of bound-state parameters from dispersive sum rules. https://doi.org/10.1134/s1063778810100121

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