Partial wave analysis of p̄p→π−π+, π0π0, ηη and ηη′ Original Research Article

A partial wave analysis is presented of Crystal Barrel data on View the MathML source, ηη and ηη′ from 600 to 1940 MeV/c, combined with earlier data on dσ/dΩ and P for View the MathML source. The following s-channel I=0 resonances are identified: (i) JPC=5−− with mass and width (M, Γ) at (2295±30, View the MathML source) MeV, (ii) JPC=4++ at (2020±12, 170±15) MeV and (2300±25, 270±50) MeV, (iii) View the MathML sourceJPC=3−− at (1960±15, 150±25) MeV and (2210±40, 360±55) MeV, and a View the MathML source state at (View the MathML source MeV, (iv) JPC=2++ at (1910±30, 260±40) MeV, (2020±30, 275±35) MeV, (2230±30, 245±45) MeV, and (2300±35, 290±50) MeV, (v) JPC=1−− at (2005±40, 275±75) MeV, and (2165±40, View the MathML source) MeV, and (vi) JPC=0++ at (2005±30, 305±50) MeV, (2105±15, 200±25) MeV, and (2320±30, 175±45) MeV. In addition, there is a less well defined 6++ resonance at 2485±40 MeV, with Γ=410±90 MeV. For every JP, almost all these resonances lie on well defined linear trajectories of mass squared versus excitation number. The slope is 1.10±0.03 GeV2 per excitation. The View the MathML source has strong coupling to ηη, but much weaker coupling to π0π0. Its flavour mixing angle between View the MathML source and View the MathML source is (59–71.6)°, i.e. dominant decays to View the MathML source. Such decays and its strong production in View the MathML source interactions strongly suggest exotic character.