π-π scattering lengths at finite temperature

Determination of the S - wave ππ scattering lengths from a study of K ± → π ± π 0 π 0 decays

We report the results from a study of the full sample of ∼ 6.031 × 10 K → πππ decays recorded by the NA48/2 experiment at the CERN SPS. As first observed in this experiment, the ππ invariant mass (M00) distribution shows a cusp-like anomaly in the region around M00 = 2m+, where m+ is the charged pion mass. This anomaly has been interpreted as an effect due mainly to the final state charge excha...

Results from NA 48 / 2 on ππ scattering lengths measurements in K ± → π + π − e ± ν and K ± → π 0 π 0 π ± decays

Determination of ππ scattering lengths from measurement of π+π− atom lifetime

B. Adeva a, L. Afanasyev b, M. Benayoun c, A. Benelli d, Z. Berka e, V. Brekhovskikh f, G. Caragheorgheopol g, T. Cechak e, M. Chiba h, P.V. Chliapnikov f, C. Ciocarlan g, S. Constantinescu g, S. Costantini i, C. Curceanu (Petrascu) g, P. Doskarova e, D. Dreossi k, D. Drijard l,∗, A. Dudarev b, M. Ferro-Luzzi l, J.L. Fungueiriño Pazos a, M. Gallas Torreira l,a, J. Gerndt e, P. Gianotti j, D. Go...

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

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...