Evidence for the decays of Lambda(+)(C) -> Sigma(+) eta and Sigma(+) eta '

Abstract

We study the hadronic decays of Lambda(+)(C) to the final states Sigma(+) eta and Sigma(+) eta', using an e(+) e(-) annihilation data sample of 567 pb(-1) taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII collider. We find evidence for the decays Lambda(+)(C) -> Sigma(+) eta and Sigma(+) eta' with statistical significance of and, respectively. Normalizing to the reference decays Lambda(+)(C) -> Sigma(+) pi(0) and Sigma(+) omega, we obtain the ratios of the branching fractions B(Lambda(+)(C) -> Sigma(+) eta)/B(Lambda(+)(C) -> Sigma(+) pi(0)) and B(Lambda(+)(C) -> Sigma(+) eta')/B(Lambda(+)(C) -> Sigma(+) omega) to be 0.35 +/- 0.16 +/- 0.02 and 0.86 +/- 0.34 +/- 0.04, respectively. The upper limits at the 90% confidence level are set to be B(Lambda(+)(C) -> Sigma(+) eta)/B(Lambda(+)(C) -> Sigma(+) pi(0)) < 0.58 and B(Lambda(+)(C) -> Sigma(+) eta')/B(Lambda(+)(C) -> Sigma(+) omega) < 1.2. Using BESIII measurements of the branching fractions of the reference decays, we determine B(Lambda(+)(C) -> Sigma(+) eta) = (0.41 +/- 0.19 +/- 0.05)% (<0.68%) and B(Lambda(+)(C) -> Sigma(+) eta') = (1.34 +/- 0.53 +/- 0.19)% (<1.9%). Here, the first uncertainties are statistical and the second systematic. The obtained branching fraction of Lambda(+)(C) -> Sigma(+) eta is consistent with the previous measurement, and the branching fraction of Lambda(+)(C) -> Sigma(+) eta' is measured for the first time.