BESIII has made great progress in taking data which is the largest data samples near the $\Lambda_{ c}^{ +}\bar{ \Lambda}_{ c}^{ -}$ threshold. We have measured the branching fraction of $\Lambda_{ c}^{ +}\to n\pi^{ +}$ to be $(6.6\pm 1.2_{ \mathrm{ stat.}}\pm 0.4_{ \mathrm{ syst.}})\times 10^{ -4}$ with the statistical significance of 7.3 $\sigma$ firstly using $3.9\mathrm{ fb}^{ -1}$ $e^{ +}e^{ -}$ collision collected with BESIII detector at six center-of-mass energies between 4.612 and 4.699 GeV. With the result of the branching fraction of $\Lambda_{ c}^{ +}\to p\pi^{ 0}$ from Belle, the ratio of the branching fractions between $\Lambda_{ c}^{ +}\to n\pi^{ +}$ and $\Lambda_{ c}^{ +}\to p\pi^{ 0}$ is measured to be larger than 7.2 at 90% confidence level. The branching fractions of $\Lambda_{ c}^{ +}\to \Lambda \pi^{ +}$ and $\Lambda_{ c}^{ +}\to \Sigma^{ 0} \pi^{ +}$ are measured to be $(1.31\pm 0.08_{ \mathrm{ stat.}}\pm 0.05_{ \mathrm{ syst.}})\times 10^{ -2}$ and $(1.22\pm 0.08_{ \mathrm{ stat.}}\pm 0.07_{ \mathrm{ syst.}})\times 10^{ -2}$, respectively, which are consistent with previous BESIII results. More results of $\Lambda_{ c}^{ +}$ decays will be published with better precision this year using $6.4\mathrm{ fb}^{ -1}$ $e^{ +}e^{ -}$ collision data samples between 4.600 and 4.946 GeV.
Categories: hep-ex