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

Using e+e− annihilation data corresponding to a total integrated luminosity of 6.32 fb−1 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 Ds+ → K−K+π+π+π− and determine the relative fractions and phases of different intermediate processes. Absolute branching fraction of Ds+→ K−K+π+π+π− decay is measured to be (6.60 ± 0.47stat.± 0.38syst.) × 10−3. The dominant intermediate process is Ds+→ a1(1260)+ϕ, ϕ → K−K+, a1(1260)+→ ρπ+, ρ → π+π−, with a branching fraction of (5.15 ± 0.41stat.± 0.32syst.) × 10−3. [Figure not available: see fulltext.]