Çetin, Serkant Ali2020-11-062020-11-062016-10-122470-00292470-0010https://hdl.handle.net/11411/2503https://doi.org/10.1103/PhysRevD.94.072004Using 482 pb(-1) of e(+) e(-) collision data collected at a center-of-mass energy of root s = 4.009 GeV with the BESIII detector, we measure the branching fractions of the decays D-s(+) -> u(+)v(u) and D-s(+) -> tau(+)v(tau). By constraining the ratio of decay rates of Ds(+) to tau(+)v(u) and to u(+)v(u) to the Standard Model prediction, the branching fractions are determined to be B(D-s(+) -> u(+)v(u) = (0.495 +/- 0.067 +/- 0.026)% and B(D-s(+) -> tau(+)v(tau) = (4.83 +/- 0.65 +/- 0.26)% Using these branching fractions, we obtain a value for the decay constant f(Ds+) of (241.0 +/- 16.3 +/- 6.5) MeV, where the first error is statistical and the second systematic.eninfo:eu-repo/semantics/openAccessB-MESONSArticle2-s2.0-8499170199810.1103/PhysRevD.94.072004Q1WOS:000385632500002