title: Practical Parametrization for Line Shapes of Near-Threshold States.
abstract: Numerous quarkonium(like) states lying near S-wave thresholds are observed experimentally. We propose a self-consistent approach to these near-threshold states compatible with unitarity and analyticity. The underlying coupled-channel system includes a bare pole and an arbitrary number of elastic and inelastic channels treated fully nonperturbatively. The resulting analytical parametrization is ideally suited for a combined analysis of the data available in various channels that is exemplified by an excellent overall description of the data for the charged Z(b)(10610) and Z(b)(10650) states.
authors.affiliation: Forschungszentrum Jülich, Institute for Advanced Simulation, Institut für Kernphysik (Theorie) and Jülich Center for Hadron Physics, D-52425 Jülich, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Hanhart
authors.affiliation: Institute for Theoretical and Experimental Physics, Bolshaya Cheremushkinskaya 25, 117218 Moscow, Russia.
authors.forename: Yu S
authors.initials: YS
authors.lastname: Kalashnikova
authors.affiliation: Forschungszentrum Jülich, Institute for Advanced Simulation, Institut für Kernphysik (Theorie) and Jülich Center for Hadron Physics, D-52425 Jülich, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Matuschek
authors.affiliation: Institute for Theoretical and Experimental Physics, Bolshaya Cheremushkinskaya 25, 117218 Moscow, Russia.|National Research Nuclear University MEPhI, Kashirskoe highway 31, 115409 Moscow, Russia.|Moscow Institute of Physics and Technology, 9 Institutskiy pereulok, Dolgoprudny, 141700 Moscow Region, Russia.
authors.forename: R V
authors.initials: RV
authors.lastname: Mizuk
authors.affiliation: Institute for Theoretical and Experimental Physics, Bolshaya Cheremushkinskaya 25, 117218 Moscow, Russia.|National Research Nuclear University MEPhI, Kashirskoe highway 31, 115409 Moscow, Russia.|Moscow Institute of Physics and Technology, 9 Institutskiy pereulok, Dolgoprudny, 141700 Moscow Region, Russia.
authors.forename: A V
authors.initials: AV
authors.lastname: Nefediev
authors.affiliation: Forschungszentrum Jülich, Institute for Advanced Simulation, Institut für Kernphysik (Theorie) and Jülich Center for Hadron Physics, D-52425 Jülich, Germany.
authors.forename: Q
authors.initials: Q
authors.lastname: Wang