The renormalized coupling gR defined through the connected four-point function at zero external momentum in the nonlinear O(3) sigma model in two dimensions is computed in the continuum form factor bootstrap approach with an estimated error ∼0.3%. New high precision data are presented for gR in the lattice-regularized theory with the standard action for nearly thermodynamic lattices L/ξ∼7 and correlation lengths ξ up to ∼122 and with the fixed point action for correlation lengths up to ∼12. The agreement between the form factor and lattice results is within ∼1%. We also recompute the phase shifts at low energy by measuring two-particle energies at finite volume, a task which was previously performed by Lüscher and Wolff using the standard action, but this time using the fixed point action. Excellent agreement with the Zamolodchikov S matrix is found.
|Number of pages||11|
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Publication status||Published - Nov 1 1999|
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)