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.
|Number of pages||1440741|
|Journal||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Publication status||Published - 2001|
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Nuclear and High Energy Physics
- Mathematical Physics