Pion rescattering in two-pion decay of heavy quarkonia

✍ Scribed by T.A. Lähde; D.O. Riska

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 310 KB
• Volume: 707
• Category: Article
• ISSN: 0375-9474
• DOI: 10.1016/s0375-9474(02)00964-8

✦ Synopsis

The role of pion rescattering in ππ decay of radially excited heavy quarkonia modeled in terms of a Qππ coupling, is investigated within the framework of the covariant Blankenbecler-Sugar equation. The effects of pion rescattering (or pion exchange) are shown to be large, unless the coupling of the two-pion system to the heavy quarks is mediated by a fairly light scalar σ meson, which couples to the gradients of the pion fields. The Hamiltonian model for the quarkonium states is formed of linear scalar confining, screened one-gluon exchange and instanton induced interaction terms. The widths and energy distributions of the basic decays ψ → J/ψππ and Υ → Υ ππ are shown to be satisfactorily described by this model. The implications of this model for the decays of the Υ (3S) state are discussed.