Amplitude analysis and branching fraction measurement of the decay Ds+→ K+π+π-π0

The singly Cabibbo-suppressed decay Ds -> K+pi(+)pi(-)pi(0) is observed by using a data set corresponding to an integrated luminosity of 6.32 fb(-1) recorded by the BESIII detector at the centre-of-mass energies between 4.178 and 4.226 GeV. The first amplitude analysis of Ds+-> K+pi(+)pi(-)pi(0) reveals the sub-structures in this decay and determines the fractions and relative phases of different intermediate processes. The dominant intermediate process is Ds+ -> K-*0 rho(+), with a fit fraction of (40.5 +/- 2.8(stat.) +/- 1.5(syst.))%. With the detection efficiency based on our amplitude analysis, the absolute branching fraction for Ds+-> K+pi(+)pi(-)pi(0) is measured to be (9.75 +/- 0.54(stat.)+/- 0.17(syst.)) x 10(-3).

Automated summary

The singly Cabibbo-suppressed decay Ds -> K+pi(+)pi(-)pi(0) is observed and the fractions and relative phases of different intermediate processes are determined. The dominant intermediate process is found to be Ds+ -> K-*0 rho(+).