We explore how chiral-symmetry constraints on weak-interaction matrix elements suggest the existence of an intermediate-state σ in several different weak-interaction processes. Particular attention is directed toward recent evidence for a σ within three-body nonleptonic weak decays. The existence of a broad scalar-isoscalar ππ resonance near 500-600 MeV, the σ, has long been controversial. Afte...

The scalar – isoscalar ππ phase shifts are analysed using a separable potential model of three coupled channels (ππ , KK and an effective 2π2π system). Model parameters are fitted to two sets of solutions obtained in a recent analysis of the CERN-Cracow-Munich measurements of the πp↑ → π πn reaction on a polarized target. A relatively narrow (90 – 180 MeV) scalar resonance f0(1400− 1460) is fou...

We explore how chiral-symmetry constraints on weak-interaction matrix elements suggest the existence of an intermediate-state σ in several different weak-interaction processes. Particular attention is directed toward recent evidence for a σ within three-body nonleptonic weak decays. The existence of a broad scalar-isoscalar ππ resonance near 500-600 MeV, the σ, has long been controversial. Afte...

We calculate the shape of the ππ and ¯ K N invariant mass distributions in the b → J/ψ π and b → J/ψ ¯ K N decays that are dominated by the (1405) resonance. The weak interaction part is the same for both processes and the hadronization into the different meson–baryon channels in the final state is given by symmetry arguments. The most important feature is the implementation of the meson–baryon...

We explore how chiral-symmetry constraints on weak-interaction matrix elements point toward the existence of an intermediate-state σ in several different weak-interaction processes. Particular attention is directed toward recent evidence for a σ within three-body nonleptonic weak decays. PACS numbers: 11.30.Rd, 11.40.Ha, 14.40.Cs HIP-2000-22/TH The existence of a broad scalar-isoscalar ππ reson...

The scalar – isoscalar ππ phase shifts are analysed using a separable potential model of three coupled channels (ππ , KK and an effective 2π2π system). Model parameters are fitted to two sets of solutions obtained in a recent analysis of the CERN-Cracow-Munich measurements of the πp↑ → π πn reaction on a polarized target. A relatively narrow (90 – 180 MeV) scalar resonance f0(1400− 1460) is fou...

From a re-analysis of ππ → ππ and ππ → KK̄ data, we found for ππ S-wave interaction below 2 GeV, σ(400), f0(980), f0(1500) and f0(1780) clearly show up. f0(1370) can be included with a very small branching ratio to ππ. f0(1300) and f0(1590) are not real resonances and are due to interference effects of above resonances. The σ(400) with a width about 700 MeV is mainly produced by t-channel exchan...

The description of strong interaction physics low-lying resonances is out the valid range perturbative QCD. Chiral effective field theories (EFTs) have been developed to tackle issue. Partial wave dynamics systematic tool decode underlying and reveal properties those resonances. It extremely powerful helpful for our understanding non-perturbative regime, especially when dispersion techniques ar...

The recent observation of B d → ππ and B̄ d → ππ decay modes allows us to make a fresh isospin analysis of B → ππ transitions. We find that current experimental data can impose some model-independent constraints on the parameter space of direct CP violation in Bd → ππ and Bd → ππ. Furthermore, we establish a direct relationship between the weak phase α and the charge-averaged branching fractions...

The total cross sections of interaction of relativistic ππ atom with ordinary atoms are obtained in the eikonal approach, which takes into consideration all multiphoton exchange processes. Contribution of these processes strongly depends on the atom nucleus charge Z and varies from 1.5% for Titanium (Z = 22) to 14% for Tantalum (Z = 73) An accurate measurement of the ππ atom (dimesoatom) lifeti...