Chiral nonperturbative approach to the isoscalar s-wave ππ interaction in a nuclear medium Abstract The s-wave isoscalar amplitude for ππ scattering in a nuclear medium is evaluated using a nonperturbative unitary coupled channels method and the standard chiral Lagrangians. The method has proved successful to describe the ππ properties in the scalar isoscalar channel up to 1.2 GeV giving rise t...

Two sources of strong phases in the decays B to ππ are identified: (1) “quasi-elastic scattering” corresponding to intermediate states like ππ and ρρ, (2) “cc̄” corresponding to intermediate states like DD̄ and D∗D̄∗. Possibilities of using data to identify these two sources are discussed and illustrated. Present data suggests both sources may be significant. The decay of B → ππ may be considered ...

The σ meson in a nuclear medium through two pion photoproduction We present theoretical results for (γ, π 0 π 0) and (γ, π ± π 0) production on nucleons and nuclei in the kinematical region where the scalar isoscalar ππ amplitude is influenced by the σ pole. The final state interaction of the pions modified by the nuclear medium produces a spectacular shift of strength of the π 0 π 0 invariant ...

We study the ρ and φ decays into ππγ, ππγ using a chiral unitary approach to deal with the final state interaction of the ππ system. The final state interaction modifies only moderately the large momenta tail of the photon spectrum of the ρ → ππγ decay. In the case of φ decay the contribution to ππγ and ππγ decay proceeds via kaonic loops, which are finite, and gives a distribution of ππ invari...

In the previous work, analyzing the I=0 S-wave ππ-scattering phase-shift through a new method of Interfering Breit-Wigner amplitudes, we have shown possibility of existence of a light scalar, σ particle, by assuming a negative back-ground phaseshift, corresponding to “repulsive core” in ππ-interaction. In this work we investigate further, to what extent, σ-properties and size of core radius are...

The analysis of the poles of the ππ scattering amplitude is shown to favour a dynamical origin of the sigma meson: it is created by a strongly attractive ππ interaction in the J = 0I = 0 channel. In the limit Nc → ∞, the σ meson disappears, contrary to the case of conventional qq̄ states. Implications for the search of the scalar qq̄ and glueball states are discussed.

Both B factories BELLE 1 and BABAR 2 have reported at this conference the preliminary results of B → Kπ and B → ππ (see Table I). For the unitary angle γ ∼ 60, the ratio R = B(B → Kπ)/B(B → ππ) is conventionally predicted to lie in the region 1.3−2.0, to be compared with the experimental values of 4.0± 1.6, 2.8± 2.0 and 1.3± 0.5 obtained by CLEO , BELLE and BABAR, respectively. Hence, the expec...