The σ pole in J/ψ→ωπ+π−J/ψ→ωπ+π−

S-wave andP-wave ππ andKπ contributions to three-body decay processes in the Resonance- Spectrum Expansion

“…We observe that the RSE prediction follows the data [11] closely up to about 0.6 GeV, which is the limit of validity of the approximation (3), which neglects ss and KK contributions. The main differences between the RSE and the BES data stem from the D-wave f 2 (1270) resonance, and also from a small signal due to the f 0 (980) resonance, both not contemplated in formula (7).…”

“…For all that, it seems safe to conclude that the RSE is in fact capable of reasonably describing both the elastic scattering data of Ref. [28] and the production data of BES [11], with the same set of parameters, contrary to what was suggested by C. Hanhart in Ref. [36].…”

“…2b a comparison is shown of the RSE formula (7) with the full ππ data, obtained in Ref. [11] from J/ψ → ωππ. A few words of caution are in place here.…”

“…We shall compare our results to data taken by the BES [11], E791 [12] and FOCUS [13] collaborations. It turns out that the data can be very well described by our amplitudes.…”

“…[11] extracted from J/ψ → ωππ. In (a) we compare the RSE to the σ signal extracted from the data by BES (blue histogram), while in (b) it is compared to the full BES ππ signal.…”