Abstract:
Within the proposed method, a set of experimental data points are fitted using a
multi-channel S-matrix. Then the resonance parameters are located as its poles on an
appropriate sheet of the Riemann surface of the energy. The main advantage of the
method is that the S-matrix is constructed in such a way that it has proper analytic
structure, i.e. for any number of two-body channels, the branching at all the channel
thresholds is represented via exact analytic expressions in terms of the channel momenta.
The way the S-matrix is constructed makes it possible not only to locate multi-channel
resonances but also to extract their partial widths as well as to obtain the scattering cross-section in the channels for which no data are available. The efficiency of the
method is demonstrated by two model examples of a single-channel and a two-channel
problems, where known resonance parameters are rather accurately reproduced by fitting
the pseudo-data artificially generated using the corresponding potentials.
