Amplitude analysis and branching fraction measurement of the decay Ds+→ K+π+π−

Abstract

Using 6.32 fb⁻¹ of e⁺e⁻ collision data collected at the center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we perform an amplitude analysis of the decay $D_s^{+}$→ K⁺π⁺π⁻ and determine the amplitudes of the various intermediate states. The absolute branching fraction of $D_s^{+}$→ K⁺π⁺π⁻ is measured to be (6.11 ± 0.18_stat.± 0.11_syst.) × 10⁻³. The branching fractions of the dominant intermediate processes $D_s^{+}$→ K⁺ρ⁰, ρ⁰→ π⁺π⁻ and $D_s^{+}$→ K^*(892)⁰π⁺, K^*(892)⁰→ K⁺π⁻ are determined to be (1.96 ± 0.19_stat.± 0.23_syst.) × 10⁻³ and (1.85 ± 0.12_stat.± 0.13_syst.) × 10⁻³, respectively. The intermediate resonances f₀(500), f₀(980), and f₀(1370) are observed for the first time in this channel.