### Abstract

We construct an effective non-relativistic quantum field theory that describes bound states of π ^{+} π ^{-} pairs and their hadronic decays. We then derive a general expression for the lifetime of the ground stare at next-to-leading order in isospin breaking. Chiral perturbation theory allows one to relate the decay rate to the two S-wave ππ scattering lengths and to several low-energy constants that occur in the chiral Lagrangian. Recent predictions for the scattering lengths give τ= (2.9±0.1) × 10 ^{-15} s. This result may be confronted with π ^{+}π ^{-} lifetime measurements, like the one presently carried out at CERN.

Original language | English |
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Article number | 016008 |

Pages (from-to) | 160081-1600821 |

Number of pages | 1440741 |

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

Volume | 64 |

Issue number | 1 |

Publication status | Published - 2001 |

Externally published | Yes |

### ASJC Scopus subject areas

- Physics and Astronomy(all)
- Nuclear and High Energy Physics
- Mathematical Physics

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## Cite this

Gasser, J., Lyubovitskij, V. E., Rusetsky, A., & Gall, A. (2001). Decays of the π +π - atom.

*Physical Review D - Particles, Fields, Gravitation and Cosmology*,*64*(1), 160081-1600821. [016008].