Scalar and tensor ππ resonances in dispersive analysis

Abstract

Role of the dispersive method in analysis of the [Formula: see text] amplitudes in all important partial waves: [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] is presented. Widely discussed is the role of new (GKPY) and old (Roy) dispersion relations with imposed crossing symmetry condition. Example of a successful application of the GKPY and Roy’s equations in test of [Formula: see text] amplitudes fitted to both experimental data and dispersion relations is presented. Short and purely mathematical proof of the uniqueness and correctness of the dispersive method used to precise determination of [Formula: see text] interaction parameters is presented.