Evidence for the decays of $Lambda^+_{c}toSigma^+eta$ and $Sigma^+eta^prime$


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We study the hadronic decays of $Lambda_{c}^{+}$ to the final states $Sigma^{+}eta$ and $Sigma^+eta^prime$, 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 $Lambda_{c}^{+}rightarrowSigma^{+}eta$ and $Sigma^+eta^prime$ with statistical significance of $2.5sigma$ and $3.2sigma$, respectively. Normalizing to the reference decays $Lambda_c^+toSigma^+pi^0$ and $Sigma^+omega$, we obtain the ratios of the branching fractions $frac{{mathcal B}(Lambda_c^+toSigma^+eta)}{{mathcal B}(Lambda_c^+toSigma^+pi^0)}$ and $frac{{mathcal B}(Lambda_c^+toSigma^+eta^prime)}{{mathcal B}(Lambda_c^+toSigma^+omega)}$ to be $0.35 pm 0.16 pm 0.03$ and $0.86 pm 0.34 pm 0.07$, respectively. The upper limits at the 90% confidence level are set to be $frac{{mathcal B}(Lambda_c^+toSigma^+eta)}{{mathcal B}(Lambda_c^+toSigma^+pi^0)}<0.58$ and $frac{{mathcal B}(Lambda_c^+toSigma^+eta^prime)}{{mathcal B}(Lambda_c^+toSigma^+omega)}<1.2$. Using BESIII measurements of the branching fractions of the reference decays, we determine $mathcal B({Lambda_{c}^{+}rightarrowSigma^{+}eta})=(0.41pm0.19pm0.05)%$ ($<0.68%$) and $mathcal B({Lambda_{c}^{+}rightarrowSigma^{+}eta})=(1.34pm0.53pm0.21)%$ ($<1.9%$). Here, the first uncertainties are statistical and the second systematic. The obtained branching fraction of $Lambda_c^+toSigma^+eta$ is consistent with the previous measurement, and the branching fraction of $Lambda_{c}^{+}rightarrowSigma^{+}eta^{prime}$ is measured for the first time.

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