Using $4.5~\mathrm{fb}^{-1}$ of $e^+e^-$ collision data collected by the BESIII detector at center-of-mass energies between $4.600$ and $4.699~\mathrm{GeV}$, 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 $$\mathcal{B}(\Lambda_c^+ \to \Sigma^{\pm}\pi^{\mp}e^+\nu_e) = \left(7.7^{+2.5}_{-2.3}\,(\mathrm{stat}) \pm 1.3\,(\mathrm{syst})\right)\times10^{-4},$$ which is consistent with quark model predictions within two standard deviations.
Evidence for the semileptonic decays Λ+𝑐 →Σ±𝜋∓𝑒+𝜈𝑒
Garzia, I.;Melendi, F. M.;
2026
Abstract
Using $4.5~\mathrm{fb}^{-1}$ of $e^+e^-$ collision data collected by the BESIII detector at center-of-mass energies between $4.600$ and $4.699~\mathrm{GeV}$, 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 $$\mathcal{B}(\Lambda_c^+ \to \Sigma^{\pm}\pi^{\mp}e^+\nu_e) = \left(7.7^{+2.5}_{-2.3}\,(\mathrm{stat}) \pm 1.3\,(\mathrm{syst})\right)\times10^{-4},$$ which is consistent with quark model predictions within two standard deviations.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
