Decay Asymmetry Research Articles

Study of angular observables in exclusive semileptonic Bc decays

In this work, we investigate angular observables such as the longitudinal polarization of charged leptons, τ-polarization, and forward-backward asymmetry in semileptonic Bc decays. Additionally, we provide predictions for lepton flavor violating observables, the R ratios in the decay channels Bc→ηc(J/ψ)lνl and Bc→D(D*)lνl across the entire q2 region. Our analysis is conducted within the relativistic independent quark model, focusing on the potential model-dependent aspects of these observables. We compare our model predictions with existing lattice predictions, highlighting the strong applicability of our framework in describing Bc decays. Considering the forthcoming experimental upgrades and the Run 3 data results on Bc meson decays, rapid confirmation of these quantities could indicate significant discoveries of physics beyond the Standard Model. This may open up new avenues for understanding the complex flavor dynamics in heavy meson decays. Published by the American Physical Society 2024

Decay-angular-distribution correlated CP violation in heavy hadron cascade decays

CP violation in baryon decay processes is still undiscovered to date. We present a general analysis of the decay-angular distributions and the corresponding CP asymmetries in cascade decays of the type H→R(→ab)c, where H is a heavy hadron that decays through weak interactions H→Rc and the resonance R decays strongly via R→ab. Based on the analysis, we propose to search for CP violation in the decay-angular distributions in the cascade decay processes B→BM, with B or M subsequently decaying through strong interactions, where B is the mother baryon, B and M are the daughter baryon and meson, respectively, and M has to be spin nonzero. We also present some typical decay channels in which the search for such kinds of CP asymmetries can be performed. Published by the American Physical Society 2024

Analysis of hadronic weak decays of charmed baryons in the topological diagrammatic approach

We perform a global fit to the experimental data of two-body charmed baryon decays based on the topological diagrammatic approach (TDA) and take into account the phase shifts between S- and P-wave amplitudes as inspired by the recent BESIII measurement of the decay asymmetry in the decay Λc+→Ξ0K+. The TDA has the advantage that it is more intuitive, graphic, and easier to implement model calculations. The measured branching fractions and decay asymmetries are well accommodated in the TDA except for a few modes, in particular, the predicted B(Ξc0→Ξ−π+)=(2.83±0.10)% is larger than its current value. The equivalence of the TDA and the irreducible SU(3) approach (IRA) is established. We show that the number of the minimum set of tensor invariants in the IRA and the topological amplitudes in the TDA is the same and present their relations. The predicted magnitudes of S- and P-wave amplitudes and their phase shifts are presented for measured and yet-to-be-measured modes in both the TDA and IRA which can be tested in the near future. Besides the decay Λc+→Ξ0K+, there exist several modes which proceed only through W-exchange. In particular, the observed channel Ξc0→Σ+K− should have phase shifts similar to that in Λc+→Ξ0K+ and its decay asymmetry is predicted to be −0.21±0.17 which can be used to test our theoretical framework. In contrast, the TDA leads to a large α of order −0.93 for the decay Ξc+→Ξ0π+ even after the phase-shift effect is incorporated in the fit. Published by the American Physical Society 2024

Highly reversible transition metal migration in superstructure-free Li-rich oxide boosting voltage stability and redox symmetry

The further practical applications of Li-rich layered oxides are impeded by voltage decay and redox asymmetry, which are closely related to the structural degradation involving irreversible transition metal migration. It has been demonstrated that the superstructure ordering in O2-type materials can effectively suppress voltage decay and redox asymmetry. Herein, we elucidate that the absence of this superstructure ordering arrangement in a Ru-based O2-type oxide can still facilitate the highly reversible transition metal migration. We certify that Ru in superstructure-free O2-type structure can unlock a quite different migration path from Mn in mostly studied cases. The highly reversible migration of Ru helps the cathode maintain the structural robustness, thus realizing terrific capacity retention with neglectable voltage decay and inhibited oxygen redox asymmetry. We untie the knot that the absence of superstructure ordering fails to enable a high-performance Li-rich layered oxide cathode material with suppressed voltage decay and redox asymmetry.

Complete determination of SU(3)F amplitudes and strong phase in Λc+→Ξ0K+

The BESIII collaboration has recently reported the first time measurement of the decay asymmetry α(Λc+→Ξ0K+)=0.01±0.16(stat)±0.03(syst) and also a sizable phase shift of δP−δS=−1.55±0.25 or 1.59±0.25 between S- and P-wave amplitudes. This implies significant strong phase shifts in the decay amplitudes. The strong phases indicate the existence of rescattering or loop effects, which are challenging to calculate due to nonperturbative effects. By employing the flavor SU(3)F symmetry and applying the Körner-Pati-Woo theorem to reduce the number of parameters, we find that the current data already allow us to obtain, for the first time, model-independent decay amplitudes and their strong phases. The establishment of the existence of sizable strong phases opens a window for future investigations into CP violation. In our fit, a notable discrepancy emerges in the branching ratio of Ξc0→Ξ−π+. The direct relationship between Γ(Λc+→Λe+νe) and Γ(Ξc0→Ξ−e+νe), along with newly discovered SU(3)F relations, collectively suggests an underestimation of B(Ξc0→Ξ−π+) in experimental findings. Published by the American Physical Society 2024

Investigation of the ΔI=1/2 Rule and Test of CP Symmetry through the Measurement of Decay Asymmetry Parameters in Ξ^{-} Decays.

Using (10087±44)×10^{6} J/ψ events collected with the BESIII detector, numerous Ξ^{-} and Λ decay asymmetry parameters are simultaneously determined from the process J/ψ→Ξ^{-}Ξ[over ¯]^{+}→Λ(pπ^{-})π^{-}Λ[over ¯](n[over ¯]π^{0})π^{+} and its charge-conjugate channel. The precisions of α_{Λ0} for Λ→nπ^{0} and α[over ¯]_{Λ0} for Λ[over ¯]→n[over ¯]π^{0} compared to world averages are improved by factors of 4 and 1.7, respectively. The ratio of decay asymmetry parameters of Λ→nπ^{0} to that of Λ→pπ^{-}, ⟨α_{Λ0}⟩/⟨α_{Λ-}⟩, is determined to be 0.873±0.012_{-0.010}^{+0.011}, where the first and the second uncertainties are statistical and systematic, respectively. The ratio is smaller than unity more than 5σ, which signifies the existence of the ΔI=3/2 transition in Λ for the first time. Besides, we test for CP symmetry in Ξ^{-}→Λπ^{-} and in Λ→nπ^{0} with the best precision to date.

Charmonium decays of beauty baryons in the perturbative QCD approach

Motivated by recent advances in experimental measurements of heavy baryon decays, the charmonium decays of single b baryon are investigated systematically in the framework of perturbative QCD approach. We calculate the decay branching ratios and helicity amplitudes as well as many pertinent decay asymmetry parameters that characterize the angular decay distributions. In particular, we estimate the fragmentation fractions of b quark to b baryons based on the current world averages of the branching ratio multiplied by fragmentation fraction. Some of the featured results are compared with the predictions of other approaches and experimental data. We also evaluate the branching ratios and angular asymmetries of the Σb and Ξb′ decay modes, which have neither been measured experimentally nor calculated theoretically. Our results could be helpful for a future experimental search for them and provide deeper insights in the understanding of the dynamics of heavy-flavor weak decay processes. Published by the American Physical Society 2024

Development of a polarization monitor for the J-PARC muon g − 2/EDM experiment

In the J-PARC Muon g−2/EDM experiment, the Polarization Monitor plays a crucial role in assessing the quality of muon beams by measuring the spin polarization of muons in the muonium production chamber. This is achieved through analyzing the asymmetry in muon decay, which serves as an indicator of beam quality. The development of this detector system is segmented into three distinct phases. The initial two phases have undergone validation using atmospheric muons. A significant aspect of Phase 1 is the simulation study, which, when integrated with energy deposition calibration derived from experimental data, effectively minimizes background noise caused by muon decays within the scintillator. Furthermore, the construction of the Phase 1 apparatus has been completed, and preliminary data collection has revealed a notable difference in asymmetry between polarized and unpolarized muons. This finding is instrumental in advancing the development of Phases 2 and 3 of the detector system.

Isospin violating decays of vector charmonia

We study the isospin violating decays of vector charmonia to ΛΣ¯0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Lambda \\overline{\\Sigma }^0$$\\end{document} and its charge conjugate. They are dominated by the single photon annihilation and can be evaluated reliably with timelike form factors. We utilize the quark-pair creation model, which is valid for the OZI suppressed decays, to evaluate the form factors. We obtain the branching fractions of B(J/ψ→ΛΣ¯0+c.c.)=(2.4±0.4)×10-5\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathcal{B}(J/\\psi \\rightarrow \\Lambda \\overline{\\Sigma }^0+c.c.)=(2.4\\pm 0.4)\ imes 10^{-5}$$\\end{document} and B(ψ(2S)→ΛΣ¯0+c.c.)=(3.0±0.5)×10-6\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathcal{B}(\\psi (2\\,S)\\rightarrow \\Lambda \\overline{\\Sigma }^0+c.c.)=(3.0\\pm 0.5)\ imes 10^{-6}$$\\end{document}, which are compatible with the measurements by the BESIII collaborations, respectively. The decay asymmetries are found to be αJ/ψ=0.314\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\alpha _{J/\\psi }=0.314$$\\end{document} and αψ(2S)=0.461\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\alpha _{\\psi (2S)}=0.461$$\\end{document}, which can be examined at BESIII in the foreseeable future.

Measurement of the Time-Integrated CP Asymmetry in D^{0}→K^{-}K^{+} Decays.

The time-integrated CP asymmetry in the Cabibbo-suppressed decay D^{0}→K^{-}K^{+} is measured using proton-proton collision data, corresponding to an integrated luminosity of 5.7 fb^{-1} collected at a center-of-mass energy of 13TeV with the LHCb detector. The D^{0} mesons are required to originate from promptly produced D^{*+}→D^{0}π^{+} decays, and the charge of the companion pion is used to determine the flavor of the charm meson at production. The time-integrated CP asymmetry is measured to be A_{CP}(K^{-}K^{+})=[6.8±5.4±1.6]×10^{-4} where the first uncertainty is statistical and the second systematic. The direct CP asymmetries in D^{0}→K^{-}K^{+} and D^{0}→π^{-}π^{+} decays, a_{K^{-}K^{+}}^{d} and a_{π^{-}π^{+}}^{d}, are derived by combining A_{CP}(K^{-}K^{+}) with the time-integrated CP asymmetry difference, ΔA_{CP}=A_{CP}(K^{-}K^{+})-A_{CP}(π^{-}π^{+}), and other inputs, giving a_{K^{-}K^{+}}^{d}=(7.7±5.7)×10^{-4},a_{π^{-}π^{+}}^{d}=(23.2±6.1)×10^{-4},with a correlation coefficient corresponding to ρ=0.88. The compatibility of these results with CP symmetry is 1.4 and 3.8 standard deviations for D^{0}→K^{-}K^{+} and D^{0}→π^{-}π^{+} decays, respectively. This is the first evidence for direct CP violation in a specific D^{0} decay.

Performance study of the aerogel RICH at the Belle II experiment

The Belle II experiment at the SuperKEKB asymmetric e+e− collider in High Energy Accelerator Research Organization (KEK, Tsukuba, Japan) is searching for CP asymmetries in different rare decays in the Standard Model. We will collect a large data sample to improve precision of Standard Model measurements (of which CP asymmetries are one example) and search for New Physics. We study the Aerogel Ring Imaging Cherenkov (ARICH) detector response in terms of loglikelihood functions using decay samples of D∗+→D0π+ and D∗−→D̄0π− resonances. The particle identification efficiencies and mis-identification probabilities are presented in 2D momentum and polar angle bins.

Precision Measurement of the Decay Σ^{+}→pγ in the Process J/ψ→Σ^{+}Σ[over ¯]^{-}.

Using (10 087±44)×10^{6} J/ψ events collected with the BESIII detector, the radiative hyperon decay Σ^{+}→pγ is studied at an electron-positron collider experiment for the first time. The absolute branching fraction is measured to be (0.996±0.021_{stat}±0.018_{syst})×10^{-3}, which is lower than its world average value by 4.2 standard deviations. Its decay asymmetry parameter is determined to be -0.652±0.056_{stat}±0.020_{syst}. The branching fraction and decay asymmetry parameter are the most precise to date, and the accuracies are improved by 78% and 34%, respectively.

Estimates of exchange topological contributions and CP -violating observables in Λb→Λϕ decay

The penguin-dominated two-body weak decay of ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}\ensuremath{\phi}$ is studied based on the perturbative QCD approach. In addition to the penguin emission diagrams, the penguin exchange and $W$ exchange ones are also accounted for. It is found that the penguin exchange contribution is in fact important and comparable to the penguin emission one, while the $W$ exchange contribution is highly Cabibbo-Kobayashi-Maskawa (CKM) suppressed. The predicted branching ratio, $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}\ensuremath{\phi})={6.9}_{\ensuremath{-}2.0\ensuremath{-}1.6}^{+1.9+1.8}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, is larger than the previous theoretical estimates but in comparison with the data from Particle Data Group at the level of 1 standard deviation. We also explore some pertinent decay asymmetry parameters that characterize the angular decay distributions. The inclusion of the $W$ exchange contribution provides the nonzero weak phase difference, consequently, allowing us to estimate the direct $CP$ violation and true triple product asymmetries in the concerned process. The numerical results demonstrate that the direct $CP$ violation is at the level of a few percent, and the true triple product asymmetries are also predicted to be tiny, of order ${10}^{\ensuremath{-}2}--{10}^{\ensuremath{-}4}$. The observed small $CP$-violating observables have shown no significant deviations from zero. Our predictions will be subject to stringent tests with precise data from LHCb in the future.

Weak decays of antitriplet charmed baryons from the perspective of flavor symmetry

In this work, we carry out a global fit for the two-body weak decays of antitriplet charmed baryons in both SU(3) respected and broken scenarios incorporating all the available data up to date. In the SU(3) irreducible representation approach (IRA), more amplitudes for irreducible representation terms are taken into account and the ranges for their coefficients in each scenarios are predicted. By a comparison among various fitting schemes in this work, experimental data prefer the SU(3) symmetry breaking scenario. Observables of interest, branching fractions and decay asymmetries of all the Cabibbo-favored (CF), singly Cabibbo-suppressed (SCS) and doubly Cabibbo-suppressed (DCS) channels are calculated in the chosen fitting scheme. Most of our predictions are consistent well with experimental data. We further propose more ways to explore the SU(3) symmetry in charmed baryon decays: (i) A clear measurement of branching fraction on CF mode {Xi}_c^0to {Xi}^0{pi}^0 as a large difference exists between SU(3) respected and broken scenarios. (ii) The decay asymmetries of the five yet-to-be measured CF decay modes, {Xi}_c^0to {Lambda}^0{K}_S , Σ0KS, Ξ0π0, Ξ0η, Ξ0η′, for their opposite signs in the two different cases. (iii) The future measurement on branching fraction ratios indicated from eq. (2.10) and presented on table 7. An improved measurement for alpha left({Lambda}_c^{+}to p{K}_Sright) is called for since predictions from both fittings, including the one in current work and earlier works, and the pole model calculation prefer an opposite sign from previous experimental value. Given branching fractions of most of the CF modes and part of the SCS modes being measured, predictions for the remaining channels, including the DCS modes as well as more decay asymmetries, are anticipated to be checked by the upcoming experiments in BESIII, Belle/Belle-II and LHCb.

Search for [formula omitted] violation and measurement of branching fractions and decay asymmetry parameters for [formula omitted] and [formula omitted] ([formula omitted

We report a study of Λc+→Λh+ and Λc+→Σ0h+ (h=K,π) decays based on a data sample of 980fb-1 collected with the Belle detector at the KEKB energy-asymmetric e+e- collider. The first results of direct CP asymmetry in two-body singly Cabibbo-suppressed (SCS) decays of charmed baryons are measured, ACPdir(Λc+→ΛK+)=+0.021±0.026±0.001 and ACPdir(Λc+→Σ0K+)=+0.025±0.054±0.004. We also make the most precise measurement of the decay asymmetry parameters (α) for the four modes of interest and search for CP violation via the α-induced CP asymmetry (ACPα). We measure ACPα(Λc+→ΛK+)=-0.023±0.086±0.071 and ACPα(Λc+→Σ0K+)=+0.08±0.35±0.14, which are the first ACPα results for SCS decays of charmed baryons. We search for Λ-hyperon CP violation in Λc+→(Λ,Σ0)π+ and find ACPα(Λ→pπ-)=+0.013±0.007±0.011. This is the first time that hyperon CP violation has been measured via Cabibbo-favored charm decays. No evidence of baryon CP violation is found. We also obtain the most precise branching fractions for two SCS Λc+ decays, B(Λc+→ΛK+)=(6.57±0.17±0.11±0.35)×10-4 and B(Λc+→Σ0K+)=(3.58±0.19±0.06±0.19)×10-4. The first uncertainties are statistical and the second systematic, while the third uncertainties come from the uncertainties on the world average branching fractions of Λc+→(Λ,Σ0)π+.

Doubly charmed baryon decays Ξcc++→Ξc(′)+π+ in the quark model

In this work we study the doubly charmed baryon decays ${\mathrm{\ensuremath{\Xi}}}_{cc}^{++}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Xi}}}_{c}^{(\ensuremath{'})+}{\ensuremath{\pi}}^{+}$ within the framework of the nonrelativistic quark model (NRQM). Factorizable amplitudes are expressed in terms of transition form factors, while nonfactorizable amplitudes arising from the inner $W$ emission are evaluated using current algebra and the pole model and expressed in terms of baryonic matrix elements and axial-vector form factors. Nonperturbative parameters are then calculated using the NRQM. They can be expressed in terms of the momentum integrals of baryon wave functions, which are in turn expressed in terms of the harmonic oscillator parameters ${\ensuremath{\alpha}}_{\ensuremath{\rho}}$ and ${\ensuremath{\alpha}}_{\ensuremath{\lambda}}$ for $\ensuremath{\rho}$- and $\ensuremath{\lambda}$-mode excitation. The measured ratio $R$ of the branching fraction of ${\mathrm{\ensuremath{\Xi}}}_{cc}^{++}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}+}{\ensuremath{\pi}}^{+}$ relative to ${\mathrm{\ensuremath{\Xi}}}_{cc}^{++}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Xi}}}_{c}^{+}{\ensuremath{\pi}}^{+}$ can be accommodated in the NRQM with ${\ensuremath{\alpha}}_{\ensuremath{\rho}1}$ and ${\ensuremath{\alpha}}_{{\ensuremath{\rho}}_{2}}$ being in the vicinity of 0.51 and 0.19, respectively, where ${\ensuremath{\alpha}}_{\ensuremath{\rho}1}$ is the ${\ensuremath{\alpha}}_{\ensuremath{\rho}}$ parameter for ${\mathrm{\ensuremath{\Xi}}}_{cc}^{++}$ and ${\ensuremath{\alpha}}_{\ensuremath{\rho}2}$ for ${\mathrm{\ensuremath{\Xi}}}_{c}^{(\ensuremath{'})+}$. Decay asymmetries are predicted to be $\ensuremath{-}0.78$ and $\ensuremath{-}0.89$ for ${\mathrm{\ensuremath{\Xi}}}_{c}^{+}{\ensuremath{\pi}}^{+}$ and ${\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}+}{\ensuremath{\pi}}^{+}$ modes, respectively, which can be tested in the near future. We compare our results with other works and point out that although some other models can accommodate the ratio $R$, they tend to lead to a branching fraction of ${\mathrm{\ensuremath{\Xi}}}_{cc}^{++}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Xi}}}_{c}^{+}{\ensuremath{\pi}}^{+}$ too large compared to that inferred from the LHCb measurement of its rate relative to ${\mathrm{\ensuremath{\Xi}}}_{cc}^{++}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Lambda}}}_{c}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}$.

Analysis of angular distribution asymmetries and the associated C!P asymmetries in three-body decays of bottom baryons

We introduce a set of observables representing angular distribution asymmetries, which can be viewed as a generalization of the forward-backward asymmetry of angular distributions, and can be used as an effective tool to search for C!P violation in three-body decays of bottom and charmed baryons. We propose to search for such C!P asymmetries (1) in decays with Lambda ^0, Sigma ^pm , or Lambda _c^+ involved, such as Lambda _brightarrow Lambda ^0 D and Lambda _brightarrow Lambda ^0rho (770)^0; and (2) in three-body decays of bottom baryons with opposite parity intermediate resonances involved. Typical examples include Xi _b^-rightarrow p K^- K^-, Lambda _b^0rightarrow p K_Spi ^- and Lambda _b^0rightarrow p pi ^0pi ^-, in which the last decay channel is used as a toy model to illustrate the basic idea.

Recent Measurements of Decay Asymmetry Parameter and CP Asymmetry for Charmed Baryon Decays at Belle

We review the recent results from the Belle experiment on the measurements of branching fractions and decay asymmetry parameters (α) for the hadronic weak decays of charmed baryons, including Λc+→B+P: Λc+→(Λ,Σ0)h+ (h=π,K) and Λc+→Σ+(π0,η,η′); Ξc0→B+P: Ξc0→Ξ−π+; Ξc0→B+V: Ξc0→ΛK¯*0, Ξc0→Σ0K¯*0, and Ξc0→Σ+K*−. In addition, we present an overview of the searches for CP violation via the α-induced CP asymmetry for Λc+→(Λ,Σ0)h+ and Ξc0→Ξ−π+. Finally, we discuss the promising decay modes of Ωc0 which can be measured in the near future and are indispensable in searching for CP violation in the charm sector.

Recent Progress in Λc+ Decays

Studying Λc+ decays provides important and complementary information to help understand the effects of non-perturbative quantum chromodynamics. Recently, many interesting results about Λc+ decays have been reported thanks to the high luminosity in Belle and dedicated operation at the Λc+ pair production threshold in BESIII. This paper reviews the recent progress in experimental measurements, containing sections about the hadronic weak decay, semileptonic decay, and decay asymmetry parameters and CP violation.

Partial wave analysis of the charmed baryon hadronic decay {Lambda}_c^{+} → Λπ+π0

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^{+} → Λπ+π0 is performed, and the decays {Lambda}_c^{+} → Λρ(770)+ and {Lambda}_c^{+} → 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}^0right) , their branching fractions are determined to beBΛc+→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,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {\\displaystyle \\begin{array}{c}\\mathcal{B}\\left({\\Lambda}_c^{+}\ o \\Lambda \\rho {(770)}^{+}\\right)=\\left(4.06\\pm 0.30\\pm 0.35\\pm 0.23\\right)\ imes {10}^{-2},\\\\ {}\\mathcal{B}\\left({\\Lambda}_c^{+}\ o \\varSigma {(1385)}^{+}{\\pi}^0\\right)=\\left(5.86\\pm 0.49\\pm 0.52\\pm 0.35\\right)\ imes {10}^{-3},\\\\ {}\\mathcal{B}\\left({\\Lambda}_c^{+}\ o \\varSigma {(1385)}^0{\\pi}^{+}\\right)=\\left(6.47\\pm 0.59\\pm 0.66\\pm 0.38\\right)\ imes {10}^{-3},\\end{array}} $$\\end{document}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}^0right) and mathcal{B}left(Sigma (1385)to Lambda pi right) . In addition, the decay asymmetry parameters are measured to be αΛρ(770)+ = − 0.763 ± 0.053 ± 0.045, {alpha}_{Sigma (1385)+{pi}^0}=-0.917pm 0.069pm 0.056 , and {alpha}_{Sigma {(1385)}^0{pi}^{+}}=-0.789pm 0.098pm 0.056 .