Light σ - Meson Production in Excited Υ Decay Processes
نویسنده
چکیده
The results of analyses obtained in Part I are examined from the viewpoint of chiral symmetry. The mass spectra of ππ system are widely believed to be suppressed generally near the threshold, because of the derivative coupling property of Nambu-Goldstone π meson. However, this suppression does not hold in the processes with large energy release, and the steep increase from the ππ threshold observed in the transition Υ (3S → 1S) is shown to be consistent with general constraints from chiral symmetry.
منابع مشابه
v 1 2 3 D ec 2 00 0 103 Light σ - Meson Production in Excited Υ Decay Processes I — Analyses —
We analyze the ππ production amplitudes in the excited Υ decay processes, Υ (2S) → Υ (1S)ππ, Υ (3S) → Υ (1S)ππ and Υ (3S) → Υ (2S)ππ, and the ππ and KK̄ production amplitudes in the charmonium decay processes, ψ(2S) → J/ψππ and J/ψ → φππ, φKK. The amplitudes are parametrized by the sum of Breit-Wigner amplitudes for the σ and the other relevant particles and of the direct 2π-production amplitude...
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تاریخ انتشار 2000