First test of lepton flavor universality in the charmed baryon decays Ωc0→Ω-ℓ+νℓ using data of the Belle experiment

Physical review / D 105(9), L091101 (2022). doi:10.1103/PhysRevD.105.L091101
We present the first observation of the Ωc0→Ω-μ+νμ decay and present measurements of the branching fraction ratios of the Ωc0→Ω-ℓ+νℓ decays compared to the reference mode Ωc0→Ω-π+, (ℓ=e or μ). This analysis is based on 89.5 fb-1, 711 fb-1, and 121.1 fb-1 data samples collected with the Belle detector at the KEKB asymmetric-energy e+e- collider at the center-of-mass energies of 10.52 GeV, 10.58 GeV, and 10.86 GeV, respectively. The Ωc0 signal yields are extracted by fitting MΩℓ and MΩπ spectra. The branching fraction ratios B(Ωc0→Ω-e+νe)/B(Ωc0→Ω-π+) and B(Ωc0→Ω-μ+νμ)/B(Ωc0→Ω-π+) are measured to be 1.98±0.13(stat)±0.08(syst) and 1.94±0.18(stat)±0.10(syst), respectively. The ratio of B(Ωc0→Ω-e+νe)/B(Ωc0→Ω-μ+νμ) is measured to be 1.02±0.10(stat)±0.02(syst), which is consistent with the expectation of lepton flavor universality.
Published by Inst., Woodbury, NY