Coupled-channel system with anomalous thresholds and unitarity

A first nonperturbative and unitary treatment of multichannel systems with anomalous thresholds based on realistic potentials is presented. We consider the isospin one-half example system, $D\ensuremath{\pi}$, $D\ensuremath{\eta}$, ${D}_{s}\overline{K}$, ${D}^{*}\ensuremath{\pi}$, ${D}^{*}\ensuremath{\eta}$, ${D}^{*}\overline{K}$ coupled channels in ${J}^{P}={1}^{\ensuremath{-}}$ partial wave, chosen such that various phenomena come opening an threshold can be illustrated a stepwise procedure by suitable variation up, down strange quark masses. use set low-energy constants chiral Lagrangian were adjusted to large lattice QCD results. The six phase shifts inelasticity parameters are presented for choices pion mass. For mass 150 MeV there no encountered. small change from 145 causes dramatic impact showing our results highly relevant extrapolation calculations toward physical