Partial wave analysis of the charmed baryon hadronic decay ${\Lambda }_c^{+}\to \Lambda {\pi }^{+}{\pi }^0$

Abstract

Based on $e^{+}{e}^{-}$ collision samples corresponding to an integrated luminosity of 4.4 \mbox{fb^{-1}} collected with the BESIII detector at center-of-mass energies between $4.6\mathrm{GeV}$ and $4.7\mathrm{GeV}$, a partial wave analysis of the charmed baryon hadronic decay ${\Lambda }_c^{+}\to \Lambda {\pi }^{+}{\pi }^0$ is performed, and the decays ${\Lambda }_c^{+}\to \Lambda \rho (770{)}^{+}$ and ${\Lambda }_c^{+}\to \Sigma (1385)\pi$ are studied for the first time. Making use of the world-average branching fraction $\mathcal{B}({\Lambda }_c^{+}\to \Lambda {\pi }^{+}{\pi }^0)$, their branching fractions are determined to be \begin{eqnarray*} \begin{aligned} \mathcal{B}(\Lambda_c^+\to\Lambda\rho(770)^+)=&(4.06\pm0.30\pm0.35\pm0.23)\times10^{-2},\\ \mathcal{B}(\Lambda_c^+\to\Sigma(1385)^+\pi^0)=&(5.86\pm0.49\pm0.52\pm0.35)\times10^{-3},\\ \mathcal{B}(\Lambda_c^+\to\Sigma(1385)^0\pi^+)=&(6.47\pm0.59\pm0.66\pm0.38)\times10^{-3},\\ \end{aligned} \end{eqnarray*} where the first uncertainties are statistical, the second are systematic, and the third are from the uncertainties of the branching fractions $\mathcal{B}({\Lambda }_c^{+}\to \Lambda {\pi }^{+}{\pi }^0)$ and $\mathcal{B}(\Sigma (1385)\to \Lambda \pi )$. In addition, %according to amplitudes determined from the partial wave analysis, the decay asymmetry parameters are measured to be ${\alpha }_{\Lambda \rho (770{)}^{+}}=-0.763\pm 0.053\pm 0.045$, ${\alpha }_{\Sigma (1385{)}^{+}{\pi }^0}=-0.917\pm 0.069\pm 0.056$, and ${\alpha }_{\Sigma (1385{)}^0{\pi }^{+}}=-0.789\pm 0.098\pm 0.056$.