A bstract Based on e + e − collision samples corresponding to an integrated luminosity of 4.4 fb − 1 collected with the BESIII detector at center-of-mass energies between 4 . 6 GeV and 4 . 7 GeV, a partial wave analysis of the charmed baryon hadronic decay $$ {\Lambda}_c^{+} $$ Λc+ → Λ π + π 0 is performed, and the decays $$ {\Lambda}_c^{+} $$ Λc+ → Λ ρ (770) + and $$ {\Lambda}_c^{+} $$ Λc+ → Σ(1385) π are studied for the first time. Making use of the world-average branching fraction $$ \mathcal{B}\left({\Lambda}_c^{+}\to \Lambda {\pi}^{+}{\pi}^0\right) $$ BΛc+→Λπ+π0 , their branching fractions are determined to be $$ {\displaystyle \begin{array}{c}\mathcal{B}\left({\Lambda}_c^{+}\to \Lambda \rho {(770)}^{+}\right)=\left(4.06\pm 0.30\pm 0.35\pm 0.23\right)\times {10}^{-2},\\ {}\mathcal{B}\left({\Lambda}_c^{+}\to \varSigma {(1385)}^{+}{\pi}^0\right)=\left(5.86\pm 0.49\pm 0.52\pm 0.35\right)\times {10}^{-3},\\ {}\mathcal{B}\left({\Lambda}_c^{+}\to \varSigma {(1385)}^0{\pi}^{+}\right)=\left(6.47\pm 0.59\pm 0.66\pm 0.38\right)\times {10}^{-3},\end{array}} $$ BΛc+→Λρ770+=4.06±0.30±0.35±0.23×10−2,BΛc+→Σ1385+π0=5.86±0.49±0.52±0.35×10−3,BΛc+→Σ13850π+=6.47±0.59±0.66±0.38×10−3, where the first uncertainties are statistical, the second are systematic, and the third are from the uncertainties of the branching fractions $$ \mathcal{B}\left({\Lambda}_c^{+}\to \varLambda {\pi}^{+}{\pi}^0\right) $$ BΛc+→Λπ+π0 and $$ \mathcal{B}\left(\Sigma (1385)\to \Lambda \pi \right) $$ BΣ1385→Λπ . In addition, the decay asymmetry parameters are measured to be α Λ ρ (770)+ = − 0.763 ± 0.053 ± 0.045, $$ {\alpha}_{\Sigma (1385)+{\pi}^0}=-0.917\pm 0.069\pm 0.056 $$ αΣ1385+π0=−0.917±0.069±0.056 , and $$ {\alpha}_{\Sigma {(1385)}^0{\pi}^{+}}=-0.789\pm 0.098\pm 0.056 $$ αΣ13850π+=−0.789±0.098±0.056 .

L. J Li

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