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We present the first observation of Ωc0→Ω−μ+νμ decay and measurements branching fraction ratios Ωc0→Ω−ℓ+νℓ decays compared to reference mode Ωc0→Ω−π+, (ℓ=e or μ). This analysis is based on 89.5 fb−1, 711 121.1 fb−1 data samples collected with Belle detector at KEKB asymmetric-energy e+e− collider center-of-mass energies 10.52 GeV, 10.58 10.86 respectively. The Ωc0 signal yields are extracted by fitting MΩℓ MΩπ spectra. B(Ωc0→Ω−e+νe)/B(Ωc0→Ω−π+) B(Ωc0→Ω−μ+νμ)/B(Ωc0→Ω−π+) measured be 1.98±0.13(stat)±0.08(syst) 1.94±0.18(stat)±0.10(syst), ratio B(Ωc0→Ω−e+νe)/B(Ωc0→Ω−μ+νμ) 1.02±0.10(stat)±0.02(syst), which consistent expectation lepton flavor universality.Received 20 December 2021Accepted 26 April 2022Corrected 23 May 2022DOI:https://doi.org/10.1103/PhysRevD.105.L091101Published American Physical Society under terms Creative Commons Attribution 4.0 International license. Further distribution this work must maintain attribution author(s) published article’s title, journal citation, DOI. Funded SCOAP3.Published SocietyPhysics Subject Headings (PhySH)Research AreasBranching fractionLeptonic, semileptonic & radiative decaysPhysical SystemsCharmed baryonsTechniquesLepton collidersParticles Fields