Coarse graining $$\pi \pi $$ π π scattering

Pi Pi scattering in an effective chiral

In this talk I summarize a recently proposed mechanism to understand ππ scattering to 1 GeV. The model is motivated by the 1/NC expansion to QCD, and includes a current algebra contact term and resonant pole exchanges. Chiral symmetry plays an important role in restricting the form of the interactions. The existence of a broad low energy scalar (σ) is indicated.

What π − π scattering tells us about chiral perturbation theory

We describe a rearrangement of the standard expansion of the symmetry breaking part of the QCD effective Lagrangian that includes into each order additional terms which in the standard chiral perturbation theory (χPT) are relegated to higher orders. The new expansion represents a systematic and unambiguous generalization of the standard χPT, and is more likely to converge rapidly. It provides a...

π-N charge exchange and π +-π 0 scattering at low energies ∗

Pi-pi Scattering Lengths in the Light of Precision Measurements

pi - pi scattering in a QCD-based model field theory.

A model field theory, in which the interaction between quarks is mediated by dressed vector boson exchange, is used to analyse the pionic sector of QCD. It is shown that this model, which incorporates dynamical chiral symmetry breaking, asymptotic freedom and quark confinement, allows one to calculate fπ, mπ, rπ and the partial wave amplitudes in π-π scattering and obtain good agreement with th...