Precise Measurement of the Form Factors in <i>d</i>⁰ → <i>k</i>* (892)^- Μ⁺ Ν_μ, and Test of Lepton Universality with <i>d</i>⁰ → <i>k</i>* (892)^- L⁺ν_l Decays

We report a study of the semileptonic decay D-0 -> (K) over bar (0) pi(-) mu(+) nu(mu) based on a sample of 7.9 fb(-1) of ethorneannihilation data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider. The branching fraction of the decay is measured for the first time to be B(D-0 -> (K) over bar (0) pi(-) mu(+) nu(mu)) = (1.373 +/- 0.020(stat) +/- 0.023(syst))%, where the first uncertainty is statistical and the second is systematic. Based on the investigation of the decay dynamics, we find that the decay is dominated by the K* (892)(-) resonance with the branching fraction measured to be B(D-0 -> (K) over bar (0) pi(-) mu(+) nu(mu)) = (1.948 +/- 0.033(stat) +/- 0.036(syst))%. We also determine the hadronic form factors for the D-0 -> (K) over bar (0) pi(-) mu(+) nu(mu) decay to be r(V) = V(0)=A(1)(0) = 1.46 +/- 0.11(stat) +/- 0.04(syst), r(2) = A(2)(0)/A(1)(0) = 0.71 +/- 0.08(stat) +/- 0.03(syst), and A(1)(0) = 0.609 +/- 0.008(stat) +/- 0.008(syst), where V(0) is the vector form factor and A(1,2)(0) are the axial-vector form factors evaluated at q(2) = 0. The A1(0) is measured for the first time in D-0 -> (K) over bar (0) pi(-) mu(+) nu(mu) decay. Averaging the form factor parameters that we reported previously in D-0 -> K* (892)(-) (-> (K) over bar (0) pi(-))e+ nu(e) and D-0 -> (K) over bar (892)(-) (-> K- pi(0))mu(+)nu(mu) decays, we obtain V-r = 1.456 +/- 0.040(stat) +/- 0.016(syst), r(2) = 0.715 +/- 0.031(stat) +/- 0.014stat, and A1(0) = 0.614 +/- 0.005(stat) +/- 0.004(syst). This is the most precise determination of the form factor parameters to date measured in D -> K* (892) transitions, which provide the most stringent test on various theoretical models.