Study of the D-0 -> K-mu(+)nu(mu) Dynamics and Test of Lepton Flavor Universality with D-0 -> K(-)l(+)nu(l) Decays

• Using e(+)e(-) annihilation data of 2.93 fb(-1) collected at center-of-mass energy root s = 3.773 GeV with the BESIII detector, we measure the absolute branching fraction of D-0 -> K-mu(+)nu(mu) with significantly improved precision: BD0 -> K-mu+nu mu = (3.413 +/- 0.019(stat) +/- 0.035(syst))%. Combining with our previous measurement of BD0 -> K-e+nu e, the ratio of the two branching fractions is determined to be BD0 -> K-mu+nu mu/BD0 -> K-e+nu e = 0.974 +/- 0.007(stat) +/- 0.012(syst), which agrees with the theoretical expectation of lepton flavor universality within the uncertainty. A study of the ratio of the two branching fractions in different four-momentumtransfer regions is also performed, and no evidence for lepton flavor universality violation is found with current statistics. Taking inputs from global fit in the standard model and lattice quantum chromodynamics separately, we determine f(+)(K)(0) = 0.7327 +/- 0.0039(stat) +/- 0.0030(syst) and vertical bar V-cs vertical bar = 0.955 +/- 0.005(stat) +/- 0.004(syst) +/- 0.024(LQCD).

Subject headings

NATURVETENSKAP  -- Fysik -- Subatomär fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Subatomic Physics (hsv//eng)

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