Using 230.2 fb−1 of e+e− annihilation data collected with the BABAR detector at and near the peak of the Υ(4S) resonance, 489±55 events containing the pure leptonic decay D+s→μ+νμ have been isolated in charm-tagged events. The ratio of partial widths Γ(D+s→μ+νμ)/Γ(D+s→ϕπ+) is measured to be 0.143±0.018±0.006 allowing a determination of the pseudoscalar decay constant fDs=(283±17±7±14) MeV. The errors are statistical, systematic, and from the D+s→ϕπ+ branching ratio, respectively.Received 1 August 2006DOI:https://doi.org/10.1103/PhysRevLett.98.141801©2007 American Physical Society

Using 230.2 fb-1 of e+e- annihilation data collected with the BABAR detector at and near the peak of the Upsilon(4S) resonance, 489+/-55 events containing the pure leptonic decay Ds+-->micro;+numicro have been isolated in charm-tagged events. The ratio of partial widths Gamma(D+-->micro+numicro)/Gamma(Ds+-->phipi+) is measured to be 0.143+/-0.018+/-0.006 allowing a determination of the pseudoscalar decay constant fDs=(283+/-17+/-7+/-14) MeV. The errors are statistical, systematic, and from the Ds+-->phipi+ branching ratio, respectively.

We measure the branching ratios of the Cabibbo-suppressed decays Lambda(+)(c)->Lambda K+ and Lambda(+)(c)->Sigma K-0(+) relative to the Cabibbo-favored decay modes Lambda(+)(c)->Lambda pi(+) and Lambda(+)(c)->Sigma(0)pi(+) to be 0.044 +/- 0.004 (stat.)+/- 0.003 (syst.) and 0.038 +/- 0.005 (stat.)+/- 0.003 (syst.), respectively. We set an upper limit on the branching ratio at the 90% confidence level for Lambda(+)(c)->Lambda K+pi(+)pi(-) of 4.1x10(-2) relative to Lambda(+)(c)->Lambda pi(+), and for Lambda(+)(c)->Sigma K-0(+)pi(+)pi(-) of 2.0x10(-2) relative to Lambda(+)(c)->Sigma(0)pi(+). We also measure the branching fraction for the Cabibbo-favored mode Lambda(+)(c)->Sigma(0)pi(+) relative to Lambda(+)(c)->Lambda pi(+) to be 0.977 +/- 0.015 (stat.)+/- 0.051 (syst.). This analysis was performed using a data sample with an integrated luminosity of 125 fb(-1) collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC.

We present a measurement of the partial branching fractions and mass spectra of the exclusive radiative penguin processes B-->Kpipigamma in the range m(Kpipi)<1.8 GeV/c(2). We reconstruct four final states: K(+)pi(-)pi(+)gamma, K(+)pi(-)pi(0)gamma, K(S)(0)pi(-)pi(+)gamma, and K(S)(0)pi(+)pi(0)gamma, where K(S)(0)-->pi(+)pi(-). Using 232 x 10(6) e(+)e(-)-->BB events recorded by the BABAR experiment at the SLAC PEP-II asymmetric-energy storage ring, we measure the branching fractions B(B(+)-->K(+)pi(-)pi(+)gamma)=[2.95+/-0.13(stat)+/-0.20(syst)] x 10(-5), B(B(0)-->K(+)pi(-)pi(0)gamma)=[4.07+/-0.22(stat)+/-0.31(syst)] x 10(-5), B(B(0)-->K(0)pi(+)pi(-)gamma)=[1.85+/-0.21(stat)+/-0.12(syst)] x 10(-5), and B(B(+)-->K(0)pi(+)pi(0)gamma)=[4.56+/-0.42(stat)+/-0.31(syst)] x 10(-5).

A search for charmed baryons decaying to D(0)p reveals two states: the Lambda(c)(2880)(+) baryon and a previously unobserved state at a mass of [2939.8 +/- 1.3(stat)+/- 1.0(syst)] MeV/c(2) and with an intrinsic width of [17.5 +/- 5.2(stat)+/- 5.9(syst)] MeV. Consistent and significant signals are observed for the K-pi(+) and K-pi(+)pi(-)pi(+) decay modes of the D-0 in 287 fb(-1) annihilation data recorded by the BABAR detector at a center-of-mass energy of 10.58 GeV. There is no evidence in the D(+)p spectrum of doubly charged partners. The mass and intrinsic width of the Lambda(c)(2880)(+) baryon and relative yield of the two baryons are also measured.

We report on a study of inclusive $B^-$ and $\bar{B}^0$ meson decays to ${D^0 X}$, ${\bar{D}^0 X}$, ${D^+ X}$, ${D^- X}$, ${D_s^+ X}$, ${D_s^- X}$, ${\Lambda_c^+ X}$, ${\bar{\Lambda}_c^- X}$, based on a sample of 231 million $B\bar{B}$ events recorded with the BABAR detector at the $\Upsilon{(4S)}$ resonance. Events are selected by completely reconstructing one $B$ and searching for a reconstructed charm particle in the rest of the event. From the measured branching fractions of these decays, we infer the number of charm and anti-charm particles per $\bar{B}$ decay, separately for charged and neutral parents. We derive the total charm yield per $B^-$ decay, $n_c^- = 1.202 \pm 0.023\pm 0.040^{+0.035}_{-0.029} $, and per $\bar{B}^0$ decay, $n_c^0 = 1.193 \pm 0.030\pm 0.034^{+0.044}_{-0.035}$ where the first uncertainty is statistical, the second is systematic, and the third reflects the charm branching-fraction uncertainties. We also present the charm momentum distributions measured in the $\bar{B}$ rest frame.

We report on a study of inclusive B- and (B) over bar (0) meson decays to (DX)-X-0, (D) over bar X-0, D+X, D-X, Ds+X, Ds-X, Lambda X-+(c), (Lambda) over bar X--(c), based on a sample of 231x10(6) (B) over bar events recorded with the BABAR detector at the Y(4S) resonance. Events are selected by completely reconstructing one B and searching for a reconstructed charm particle in the rest of the event. From the measured branching fractions of these decays, we infer the number of charm and anticharm particles per (B) over bar decay, separately for charged and neutral parents. We derive the total charm yield per B- decay, n(c)(-)=1.208 +/- 0.023 +/- 0.040(-0.029)(+0.035), and per (B) over bar (0) decay, n(c)(0)=1.203 +/- 0.030 +/- 0.034(-0.035)(+0.044) where the first uncertainty is statistical, the second is systematic, and the third reflects the charm branching-fraction uncertainties. We also present the charm momentum distributions measured in the (B) over bar rest frame.

A search has been made for the decays B+ ->phi pi+ and B0->to phi pi0 in a data sample of approximately 232 x 10^6 B Bbar pairs recorded at the Upsilon(4S) resonance with the BaBar detector at the PEP-II B-meson Factory at SLAC. No significant signals have been observed, and therefore upper limits have been set on the branching fractions: BR(B+ ->phi pi+)<2.4 x 10^{-7} and BR(B0->phi pi0)<2.8 x 10^{-7} at 90% probability.

We report on a study of the decay (B) over bar (0)-> D*+omega pi(-) with the BABAR detector at the PEP-II B-factory at the Stanford Linear Accelerator Center. Based on a sample of 232x10(6) B (B) over bar decays, we measure the branching fraction B((B) over bar (0)-> D*+omega pi(-))=(2.88 +/- 0.21(stat.)+/- 0.31(syst.))x10(-3). We study the invariant mass spectrum of the omega pi(-) system in this decay. This spectrum is in good agreement with expectations based on factorization and the measured spectrum in tau(-)->omega pi(-)nu(tau). We also measure the polarization of the D*+ as a function of the omega pi(-) mass. In the mass region 1.1 to 1.9 GeV we measure the fraction of longitudinal polarization of the D*+ to be Gamma(L)/Gamma=0.654 +/- 0.042(stat.)+/- 0.016(syst.). This is in agreement with the expectations from heavy-quark effective theory and factorization assuming that the decay proceeds as (B) over bar (0)-> D*+rho(1450)(-), rho(1450)(-)->omega pi(-).

We present a preliminary measurement of the branching fraction and CP-violating parameters S and C for the decay B->omegaKs. The data sample corresponds to 232x10^6 BBbar pairs produced from e+e- annihilation at the Upsilon(4S) resonance. We measure B(omegaK0)=(5.9+/-1.0+/-0.4)x10^-6, S=0.50+0.34-0.38+/-0.02 and C=-0.56+0.29-0.27+/-0.03.

We present measurements of the $B\ensuremath{\rightarrow}\ensuremath{\eta}K\ensuremath{\gamma}$ branching fractions and upper limits for the $B\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}K\ensuremath{\gamma}$ branching fractions. For ${B}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{K}^{+}\ensuremath{\gamma}$ we also measure the time-integrated charge asymmetry. The data sample, collected with the BABAR detector at the Stanford Linear Accelerator Center, represents $232\ifmmode\times\else\texttimes\fi{}{10}^{6}$ produced $B\overline{B}$ pairs. The results for branching fractions and upper limits at 90% confidence level in units of ${10}^{\ensuremath{-}6}$ are: $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}\ensuremath{\eta}{K}^{0}\ensuremath{\gamma})={11.3}_{\ensuremath{-}2.6}^{+2.8}\ifmmode\pm\else\textpm\fi{}0.6$, $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{K}^{+}\ensuremath{\gamma})=10.0\ifmmode\pm\else\textpm\fi{}1.3\ifmmode\pm\else\textpm\fi{}0.5$, $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{K}^{0}\ensuremath{\gamma})<6.6$, $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{K}^{+}\ensuremath{\gamma})<4.2$. The charge asymmetry in the decay ${B}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{K}^{+}\ensuremath{\gamma}$ is ${\mathcal{A}}_{\mathrm{ch}}=\ensuremath{-}0.09\ifmmode\pm\else\textpm\fi{}0.12\ifmmode\pm\else\textpm\fi{}0.01$. The first errors are statistical and the second systematic.

We present results of a search for the X(3872) in B0→X(3872)K0S,X(3872)→J/ψπ+π−, improved measurements of B−→X(3872)K−, and a study of the J/ψπ+π− mass region above the X(3872). We use 232×106 B¯¯¯B pairs collected at the Υ(4S) resonance with the BABAR detector at the PEP-II e+e− asymmetric-energy storage rings. The results include the 90% confidence interval 1.34×10−6

A search has been made for the decays B+-\u003ephi pi(+) and B-0 -\u003ephi pi(0) in a data sample of approximately 232x10(6) B (B) over bar pairs recorded at the Upsilon(4S) resonance with the BABAR detector at the PEP-II B-meson Factory at SLAC. No significant signals have been observed, and therefore upper limits have been set on the branching fractions: B(B+-\u003ephi pi(+)) phi pi(0))\u003c 2.8x10(-7) at 90% probability.

We study the two-body decays of B+/- mesons to K+/- and a charmonium state X-c(c) over bar in a sample of 210.5 fb(-1) of data from the BABAR experiment. We perform measurements of absolute branching fractions B(B+/- -> K+/-Xc(c) over bar) using a missing mass technique, and report several new or improved results. In particular, the upper limit B(B+/- -> K+/-X(3872)) < 3.2 x 10(-4) at 90% C.L. and the inferred lower limit B(X(3872) -> J/psi pi(+)pi(-)) > 4.2% will help in understanding the nature of the recently discovered X(3872).