Evidence for the semileptonic decays ${\Lambda }_c^{+}\to {\Sigma }^{\pm }{\pi }^{\mp }{e}^{+}{\nu }_e$

Abstract

Using $4.5f{b}^{-1}$ of $e^{+}{e}^{-}$ collision data collected by the BESIII detector at center-of-mass energies between $4.600$ and $4.699GeV$, we search for the semileptonic decays ${\Lambda }_c^{+}\to {\Sigma }^{+}{\pi }^{-}{e}^{+}{\nu }_e$ and ${\Lambda }_c^{+}\to {\Sigma }^{-}{\pi }^{+}{e}^{+}{\nu }_e$ for the first time. Assuming their branching fractions are equal under isospin symmetry, evidence for ${\Lambda }_c^{+}\to {\Sigma }^{\pm }{\pi }^{\mp }{e}^{+}{\nu }_e$ is reported with a significance of $3.6\sigma$. The corresponding branching fraction is measured to be $\mathcal{B}({\Lambda }_c^{+}\to {\Sigma }^{\pm }{\pi }^{\mp }{e}^{+}{\nu }_e)=(7.7_{-2.3_{stat.}}^{+2.5}\pm 1.3_{syst.})\times 10^{-4}$, which is consistent with quark model predictions within two standard deviations.

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Cited by in corpus (1)

• Puzzles in charmed baryon semileptonic decays with $SU(3{)}_F$ flavor symmetry and lattice inputs