Test of Lepton Universality and Measurement of the Form Factors of D^{0}→K^{*}(892)^{-}μ^{+}ν_{μ}.

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One of the main goals of studying semileptonic decays in flavor physics is to gain a better understanding of hadronic transitions in the nonperturbative region of Quantum Chromodynamics. This involves measuring Cabibbo-Kobayashi-Maskawa matrix elements, understanding form factors, and comparing them with theoretical predictions. We report a first study of the semileptonic decay D^{0}→K^{-}π^{0}μ^{+}ν_{μ} by analyzing an e^{+}e^{-} annihilation data sample of 7.93 fb^{-1} collected at the center-of-mass energy of 3.773GeV with the BESIII detector. The absolute branching fraction of D^{0}→K^{-}π^{0}μ^{+}ν_{μ} is measured for the first time, providing necessary input for extracting the c→s Cabibbo-Kobayashi-Maskawa matrix element through this process. This measurement allows us to test lepton flavor universality, with no indication of violation found. Furthermore, a series of hadronic form factors have been determined and compared with theoretical predictions, which will impose stricter constraints on theoretical models.