Measurement of the branching fraction of DDs+ →†’ τ+ντ„ via τ„+ →†’ μ+νμ[nu over bar]τ 

• Utilizing 7.33 fb(-1) of e(+)e(-) collision data taken at the center-of-mass energies of 4.128, 4.157, 4.178, 4.189, 4.199, 4.209, 4.219, and 4.226 GeV with the BESIII detector, the branching fraction of the leptonic decay D+s+ -> tau(+)nu(tau) via tau(+) -> mu(+)nu(mu )is measured to be BD+s ->tau+nu tau = (5.37 +/- 0.17(stat) +/- 0.15(syst))%. Combining this branching fraction with the world averages of the measurements of the masses of tau(+) and D-s(+) as well as the lifetime of D-s(+) , we extract the product of the decay constant of D-s(+) and the c -> s Cabibbo-Kobayashi-Maskawa matrix element to be D- f(s)+ |V-cs| = (246.7 +/- 3.9(stat) +/- 3.6(syst)) MeV. Taking |V-cs| from a global fit in the standard model we obtain fD+s = (253.4 +/- 4.0(stat) +/- 3.7(syst)) MeV. Conversely, taking( f)D(s)(+) from lattice quantum chromodynamics calculations, we obtain |V-cs| = 0.987 +/- 0.016(stat) +/- 0.014(syst).

Ämnesord

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

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

Nyckelord

e(+)-e(-) Experiments

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)