φ →π⁺π⁻ decay within a chiral unitary approach

Abstract

Starting from the chiral perturbation theory Lagrangian, but keeping different masses for the charged and neutral mesons (m_u ≠ m_d), and using a previously developed nonperturbative unitary scheme that generates the lightest meson-meson resonances, we construct KK̅→KK̅ and KK̅→π⁺π⁻ in the vector channel. This allows us to obtain the kaon-loop contribution to φ-ρ mixing and study the φ→π⁺π⁻ decay. The dominant contribution to this decay comes from the φ→ϒ→π⁺π⁻ process. However, there can be large interferences with the subdominant contributions coming from φ-ρ and φ-ω mixing, or of these two contributions among themselves. As a consequence, a reliable measurement of φ→π⁺π⁻ decay could be used to differentiate between some φ-ω mixing scenarios proposed in the literature.