Model-independent resonance parameter extraction using the trace of K   and T matrices
  A model-independent method for the determination of Breit-Wigner resonance parameters is presented. The method is based on eliminating the dependence on the choice of channel basis by analyzing the trace of the K and T matrices in the coupled-channel formalism, rather than individual matrix elements of the multichannel scattering matrix. 
S. Ceci, A. Svarc, B. Zauner, M. Manley and S. Capstick