Abstract
This Letter presents the first lattice QCD computation of the coupled channel scattering amplitudes at energies near 1405 MeV. These amplitudes contain the resonance with strangeness and isospin, spin, and parity quantum numbers . However, whether there is a single resonance or two nearby resonance poles in this region is controversial theoretically and experimentally. Using single-baryon and meson-baryon operators to extract the finite-volume stationary-state energies to obtain the scattering amplitudes at slightly unphysical quark masses corresponding to and , this study finds the amplitudes exhibit a virtual bound state below the threshold in addition to the established resonance pole just below the threshold. Several parametrizations of the two-channel matrix are employed to fit the lattice QCD results, all of which support the two-pole picture suggested by SU(3) chiral symmetry and unitarity.
- Received 28 July 2023
- Revised 15 November 2023
- Accepted 7 December 2023
DOI:https://doi.org/10.1103/PhysRevLett.132.051901
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Published by the American Physical Society