New results on ππ phase shifts between 600 and 1900 MeV Original Research Article

With a new formulation for ππ amplitudes and some guidance from other new experimental results, we re-analyse the old CERN-Munich data for the reaction π−p → π−π+n at 17.2 GeV and also the Argonne and Brookhaven data on π+π− → KK. The formalism allows specifically for 2π, KK and 4π channels. Apart from the well-known resonances ρ(770), f2(1270) and ρ3(1690), the CERN-Munich data demand the presence of f0(1525) and ρ(1700). The data on π+π− → KK demand the presence of f0(1370). The f0(1370) and f0(1525) are included with elastic and full widths fitted simultaneously to the Crystal Barrel data. For f0(1370), Mr = 1300 ± 15 MeV, г2π = 60 ± 20 MeV, гKK = 80 ± 30 MeV, гtot = 230 ± 15 MeV; for f0(1525)Mr = 1500 ± 8 MeV, г2π = 60 ± 12 MeV, гKK = 5.8 ± 2.7 MeV, θtot = 132 ± 15 MeV. The ππ S-wave intensity has an interesting spectrum, with resonances appearing as dips. The implication of this in other related reactions is discussed.