### Abstract

The renormalized coupling g_{R} 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 g_{R} 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.

Original language | English |
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Pages (from-to) | 1-11 |

Number of pages | 11 |

Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |

Volume | 60 |

Issue number | 9 |

Publication status | Published - Nov 1 1999 |

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### ASJC Scopus subject areas

- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)

### Cite this

*Physical Review D - Particles, Fields, Gravitation and Cosmology*,

*60*(9), 1-11.