Measurement of the pseudoscalar decay constant fDs using charm-tagged events in e+e- collisions at √s=10.58 GeV

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 D-s(+)->mu(+)nu(mu) have been isolated in charm-tagged events. The ratio of partial widths Gamma(D-s(+)->mu(+)nu(mu))/Gamma(D-s(+)->phi pi(+)) is measured to be 0.143 +/- 0.018 +/- 0.006 allowing a determination of the pseudoscalar decay constant f(Ds)=(283 +/- 17 +/- 7 +/- 14) MeV. The errors are statistical, systematic, and from the D-s(+)->phi pi(+) branching ratio, respectively

Observation of B meson decays to b(1)pi and b(1)K

We present the results of searches for decays of B mesons to final states with a b(1) meson and a charged pion or kaon. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 382x10(6) B(B)over bar pairs produced in e(+)e(-) annihilation. The results for the branching fractions are, in units of 10(-6), B(B+ -> b(1)(0)pi(+)) = 6.7 +/- 1.7 +/- 1.0, B(B+ -> b(1)(0)K(+)) = 9.1 +/- 1.7 +/- 1.0, B(B-0 -> b(1)(-/+)pi +/- ) = 10.9 +/- 1.2 +/- 0.9, and B(B-0 -> b(1)(-)K(+)) = 7.4 +/- 1.0 +/- 1.0, with the assumption that B(b(1) -> omega pi) = 1. We also measure charge and flavor asymmetries A(ch)(B+ -> b(1)(0)pi(+)) = 0.05 +/- 0.16 +/- 0.02, A(ch)(B+ -> b(1)(0)K(+)) = -0.46 +/- 0.20 +/- 0.02, A(ch)(B-0 -> b(1)(-/+)pi +/- ) = -0.05 +/- 0.10 +/- 0.02, C(B-0 -> b(1)(-/+)pi +/- ) = -0.22 +/- 0.23 +/- 0.05, Delta C(B-0 -> b(1)(-/+)pi +/- ) = -1.04 +/- 0.23 +/- 0.08, and A(ch)(B-0 -> b(1)(-)K(+)) = -0.07 +/- 0.12 +/- 0.02. The first error quoted is statistical, and the second systematic

Amplitude analysis of the decay D0→K-K+π0

Using 385 fb(-1) of e(+)e(-) collisions, we study the amplitudes of the singly Cabibbo-suppressed decay D-0 -> K-K+pi(0). We measure the strong phase difference between the (D) over bar (0) and D-0 decays to K-*(892)K-+(-) to be -35.5 degrees +/- 1.9 degrees(stat)+/- 2.2 degrees(syst), and their amplitude ratio to be 0.599 +/- 0.013(stat)+/- 0.011(syst). We observe contributions from the K pi and K-K+ scalar and vector amplitudes, and analyze their angular moments. We find no evidence for charged kappa, nor for higher spin states. We also perform a partial-wave analysis of the K-K+ system in a limited mass range

Observation of Decays B0→Ds(∗)+π−B^0 \to D^{(*)}_s + \pi^- and B0→Ds(∗)−K+B^0\to D^{(*)}_s - K^+

7 pages, 2 postscript figues, submitted to Physical Review Letters - P. Grenier aussi au LPCWe report the observation of decays B0->D_s(*)+pi- and B0->D_s(*)-K+ in a sample of 230*10^6 Upsilon(4S)->BBbar events recorded with the BaBar detector at the PEP-II asymmetric-energy e+e- storage ring. We measure the branching fractions B(B0->D_s+pi-)=(1.3 +/- 0.3 (stat.) +/- 0.2 (syst.))*10^{-5}, B(B0->D_s-K+)=(2.5 +/- 0.4 (stat.) +/- 0.4 (syst.))*10^{-5}, B(B0->D_s*+pi-)=(2.8 +/- 0.6 (stat.) +/- 0.5 (syst.))*10^{-5}, and B(B0->D_s*-K+)=(2.0 +/- 0.5 (stat.) +/- 0.4 (syst.))*10^{-5}. The significance of the measurements to differ from zero are 5, 9, 6, and 5 standard deviations, respectively

The e(+)e(-)-> 2(pi(+)pi(-))pi(0), 2(pi(+)pi(-))eta, K+K-pi(+)pi(-)pi(0) and K+K-pi(+)pi(-)eta cross sections measured with initial-state radiation

We study the processes e(+)e(-)-> 2(pi(+)pi(-))pi(0)gamma, 2(pi(+)pi(-))eta gamma, K+K-pi(+)pi(-)pi(0)gamma and K+K-pi(+)pi(-)eta gamma with the hard photon radiated from the initial state. About 20 000, 4300, 5500, and 375 fully reconstructed events, respectively, are selected from 232 fb(-1) of BABAR data. The invariant mass of the hadronic final state defines the effective e(+)e(-) center-of-mass energy, so that the obtained cross sections from the threshold to about 5 GeV can be compared with corresponding direct e(+)e(-) measurements, currently available only for the eta pi(+)pi(-) and omega pi(+)pi(-) submodes of the e(+)e(-)-> 2(pi(+)pi(-))pi(0) channel. Studying the structure of these events, we find contributions from a number of intermediate states, and we extract their cross sections where possible. In particular, we isolate the contribution from e(+)e(-)->omega(782)pi(+)pi(-) and study the omega(1420) and omega(1650) resonances. In the charmonium region, we observe the J/psi in all these final states and several intermediate states, as well as the psi(2S) in some modes, and we measure the corresponding branching fractions

Measurement of the branching fraction and time-dependent CP asymmetry in the decay B-0 ->(D*+D*-KS0)

Contains fulltext : 128232.pdf (publisher's version ) (Open Access

Study of B0→ρ+ρ- decays and constraints on the CKM angle α

We present results from an analysis of B-0 ->rho(+)rho(-) decays using (383.6 +/- 4.2)x10(6) B (B) over bar pairs collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The measurements of the B-0 ->rho(+)rho(-) branching fraction, longitudinal polarization fraction f(L), and the CP-violating parameters S-long and C-long are as follows: B(B-0 ->rho(+)rho(-))=(25.5 +/- 2.1(stat)(-3.9)(+3.6)(syst))x10(-6), f(L)=0.992 +/- 0.024(stat)(-0.013)(+0.026)(syst), S-long=-0.17 +/- 0.20(stat)(-0.06)(+0.05)(syst), C-long=0.01 +/- 0.15(stat)+/- 0.06(syst). We determine the unitarity triangle angle alpha, using an isospin analysis of B ->rho rho decays. One of the two solutions, alpha=[73.1,117.0]degrees at 68% confidence level, is compatible with standard model-based fits of existing data. Constraints on the unitarity triangle are also evaluated using an SU(3) symmetry-based approach

Evidence for the B-0 -> p(p)over-barK*(0) and B+->eta K-c*(+) decays and study of the decay dynamics of B meson decays into p(p)over-barh final states

With a sample of 232x10(6) Upsilon(4S)-> B (B) over bar events collected with the BABAR detector, we study the decays of B mesons to p (p) over barh final states, where h=pi(+), K-S(0), K*(0), or K*(+). We report evidence for the B-0 -> p (p) over barK(*0) decay, with a branching fraction (1.47 +/- 0.45(stat)+/- 0.40(syst))x10(-6), and for the B+->eta K-c*(+) decay, with the branching fraction of B(B+->eta K-c*(+))xB(eta(c)-> p (p) over bar)=(1.57(-0.45)(+0.56)(stat)(-0.36)(+0.46)(syst))x10(-6), and provide improved measurements of the branching fractions of the other modes of this type. We also report the measurements of the charge asymmetry consistent with zero in the B+-> p (p) over bar pi(+), B-0 -> p (p) over barK*(0), and B+-> p (p) over barK*(+) modes. No evidence is found for the pentaquark candidate Theta(+) in the mass range 1.52 to 1.55 GeV/c(2), decaying into pK(S)(0), or the glueball candidate f(J)(2220) in the mass range 2.2 < m(p (p) over bar)< 2.4 GeV/c(2), and branching fraction limits are established for both at the 10(-7) level

Measurement of the τ-→K-π0ντ branching fraction

A measurement of the tau(-)-> K-pi(0)nu(tau) branching fraction has been made using 230.2 fb(-1) of data recorded by the BABAR detector at the PEP-II e(+)e(-) collider, located at the Stanford Linear Accelerator Center (SLAC), at a center-of-mass energy root s close to 10.58 GeV. We measure B(tau(-)-> K-pi(0)nu(tau))=(0.416 +/- 0.003(stat)+/- 0.018(syst))%