Observation of an a0-like State with Mass of 1.817 GeV in the Study of DS+ → KS0K+ π0 Decays

Using e(+)e(-) annihilation data corresponding to an integrated luminosity of 6.32 fb(-1) collected at center-of-mass energies between 4.178 and 4.226 GeV with the BESIII detector, we perform the first amplitude analysis of the decay D-s(+) -> (KSK+)-K-0 pi(0) and determine the relative branching fractions and phases for intermediate processes. We observe an a(0)-like state with mass of 1.817 GeV in its decay to (KSK+)-K-0 for the first time. In addition, we measure the ratio {B[D-s(+) -> (K*) over bar (892)K-0(+)]/B[D-s(+) -> (K-0) over bar K*(892)(+)]} to be 2.35(-0.23stat)(+0.42) +/- 0.10(syst). Finally, we provide a precision measurement of the absolute branching fraction B(D-s(+) -> (KSK+)-K-0 pi(0))=(1.46 +/- 0.06(stat) +/- 0.05(syst))%.

Automated summary

Using data from e(+)e(-) annihilation, we performed an amplitude analysis on the decay D-s(+) -> (KSK+)-K-0 pi(0) and determined the relative branching fractions and phases for intermediate processes. We observed a new state with a mass of 1.817 GeV decaying to (KSK+)-K-0 for the first time. Additionally, we measured the ratio of the branching fractions and provided a precision measurement of the absolute branching fraction.