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 Zb(10610) and Zb(10650) states.
@article{arxiv.1507.00382,
title = {A practical parametrization for line shapes of near-threshold states},
author = {C. Hanhart and Yu. S. Kalashnikova and P. Matuschek and R. V. Mizuk and A. V. Nefediev and Q. Wang},
journal= {arXiv preprint arXiv:1507.00382},
year = {2015}
}
Comments
LaTeX2e, 5 pages, 1 figure, typos corrected, version published in Phys. Rev. Lett