The study of the Cabibbo-favored semileptonic decay Λ+c → Λμ+νμ is reported using 4.5 fb−1 of e+e− annihilation data collected at center-of-mass energies ranging from 4.600 to 4.699 GeV. The branching fraction of the decay is measured to be B(Λ+c → Λμ+νμ) = (3.48 pm 0.14stat pm 0.10syst)%, 3 times more precise than the prior world average result. Tests of lepton flavor universality using Λ+c → Λl+νl (l = e, μ) decays are reported for the first time, based on measurements of the differential decay rates and the forward-backward asymmetries in separate four-momentum transfer regions. The results are compatible with Standard Model predictions. Furthermore, we improve the determination of the form-factor parameters in Λ+c → Λl+νl decays, which provide stringent tests and calibration for lattice quantum chromodynamics calculations.
Study of Λc+→Λμ+νμ and test of lepton flavor universality with Λc+→Λℓ+νℓ decays
Garzia, I.;Gramigna, S.;
2023
Abstract
The study of the Cabibbo-favored semileptonic decay Λ+c → Λμ+νμ is reported using 4.5 fb−1 of e+e− annihilation data collected at center-of-mass energies ranging from 4.600 to 4.699 GeV. The branching fraction of the decay is measured to be B(Λ+c → Λμ+νμ) = (3.48 pm 0.14stat pm 0.10syst)%, 3 times more precise than the prior world average result. Tests of lepton flavor universality using Λ+c → Λl+νl (l = e, μ) decays are reported for the first time, based on measurements of the differential decay rates and the forward-backward asymmetries in separate four-momentum transfer regions. The results are compatible with Standard Model predictions. Furthermore, we improve the determination of the form-factor parameters in Λ+c → Λl+νl decays, which provide stringent tests and calibration for lattice quantum chromodynamics calculations.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
