Unitarity and partial width for φ → 3π

Abstract

It is shown that absorptive contributions to g_{φ ρ π} coming from φ → KK¯ → 3π may account for the observed magnitude of Γ (φ → 3π ). Two complementary calculations, one based on the Gell-Mann-Sharp-Wagner model and the other based on partial-wave unitarity, are presented. It is argued that ψ (3105) and ψ (3695) are especially narrow since similar absorptive corrections are absent.