Using 2.93 fb(-1) of e(+)e(-) collision data taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, the observation of the D-0 -> K-1 (1270)(-)e(+)nu(e) semileptonic decay is ...presented. The statistical significance of the decay D-0 -> K-1 (1270)e(+)nu(e) is greater than 10 sigma. The branching fraction of D-0 -> K-1 (1270)(-)e(+)nu(e) is measured to be (1.09 +/- 0.13(-0.16)(+0.09) +/- 0.12) x 10(-3). Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of K-1 (1270)(-) -> K-pi(+)pi(-). The fraction of longitudinal polarization in D-0 -> K-1 (1270)(-)e(+)nu(e) is determined for the first time to be 0.50 +/- 0.19(stat )+/- 0.08(syst).
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We report a study of the e+e– → D+D–π+π– process using e+e– collision data samples with an integrated luminosity of 2.5 fb–1 at center-of-mass energies from 4.36 to 4.60GeV, collected with the BESIII ...detector at the BEPCII storage ring. The D1(2420)+ is observed in the D+π+π– mass spectrum. The mass and width of the D1(2420)+ are measured to be (2427.2 ± 1.0stat. ± 1.2syst.)MeV/c2 and (23.2 ± 2.3stat. ± 2.3syst.)MeV, respectively. The first errors are statistical and the second ones are systematic. In addition, the Born cross sections of the e+e– → D1(2420)+ D– + c.c. → D+D–π+π– and e+e– → ψ(3770)π+π– → D+D–π+π– processes are measured as a function of the center-of-mass energy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We report new measurements of the branching fraction B(Dv), where lis either mu or tau (-> pi), based on 6.32 fbof electron-positron annihilation data collected by the BESIII experiment at six ...center-of-mass energy points between 4.178 and 4.226 GeV. Simultaneously floating the Ds -> mu mu components yields B(D -> tau) = (5.21 +/- 0.25 +/- 0.17) x 102, B(D -> mu mu) (5.35 +/- 0.13 +/- 0.16) x 103, and the ratio of decay widths R = Gamma(D -> tau tau)/Gamma -> mu&m)= 9.73-0.58 +/- 0.36, where the first uncertainties are statistical and the second systematic. No evidence of CP asymmetry is observed in the decay rates Ds +/- -> mu +/- v mu and D +/- -> tau +/-= (+2.9 +/- 4.8 +/- 1.0)%. Constraining our measurement to the Standard Model expectation of lepton universality (R = 9.75), we find the more precise results B(D -> tau = (5.22 +/- 0.10 +/- 0.14) x 10-2and A(+/-) = (-0.1 +/- 1.9 +/- 1.0)%. Combining our results with inputs external to our analysis, we determine the C -> (S) over bar quark mixing matrix element, D+ decay constant, and ratio of the decay constants to be vertical bar V vertical bar = 0.973 +/- 0.009 +/- 0.014, f D+ = 249.9 +/- 2.4 +/- 3.5 MeV, and f D+ / f D = 1.232 +/- 0.035, respectively.
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Using 2.93 fb(-1) of e(+)e(-) collision data collected with the BESIII detector at a center-of-mass energy of 3.773 GeV, we measure the absolute branching fractions of the decays D-0 -> ...K(-)e(+)nu(e) and D+ -> (K) over bar (0)e(+)nu(e) to be (3.567 +/- 0.031(stat) +/- 0.025(syst))% and (8.68 +/- 0.14(stat) +/- 0.16(syst))%, respectively. Starting with the process e(+)e(- ) -> D (D) over bar, a new reconstruction method is employed to select events that contain candidates for both D -> (K) over bare(+)nu(e) and (D) over bar -> Ke(-)(nu) over bar (e) decays. The branching fractions reported in this work are consistent within uncertainties with previous BESIII measurements that selected events containing D -> (K) over bare(+)nu(e) and hadronic (D) over bar decays. Combining our results with the lifetimes of the D degrees and D+ mesons and the previous BESIII measurements leads to a ratio of the two decay partial widths of (Gamma) over bar (D0 -> K-e+)(nu e)/(Gamma) over bar (D+ -> (K) over bar 0e+)(nu e) = 1.039 +/- 0.021. This ratio supports isospin symmetry in the D-0 -> K(-)e(+)nu(e) and D+ -> (K) over bar (0)e(+)nu(e) decays within 1.9 sigma.
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