2,102 research outputs found
Dalitz plot analyses of B-0 -> (D-DK+)-K-0 and B+-> (D)over-bar(-)D(0)K(+) decays
No full text© 2015, APS Journal
Measurement of Collins asymmetries in inclusive production of charged pion pairs in e+e− annihilation at BABAR
No full textWe present measurements of Collins asymmetries in the inclusive process e+e−→ππX, where π stands for charged pions, at a center-of-mass energy of 10.6 GeV. We use a data sample of 468 fb−1 collected by the BABAR experiment at the PEP-II B factory at SLAC, and consider pairs of charged pions produced in opposite hemispheres of hadronic events. We observe clear asymmetries in the distributions of the azimuthal angles in two distinct reference frames. We study the dependence of the asymmetry on several kinematic variables, finding that it increases with increasing pion momentum and momentum transverse to the analysis axis, and with increasing angle between the thrust and beam axis
Measurement of the energy dependence of the ee → , and exclusive cross sections
No full textInternational audienceWe report the first measurement of the exclusive cross sections ee → , ee → , and ee → in the energy range from 10.63 GeV to 11.02 GeV. The B mesons are fully reconstructed in a large number of hadronic final states and the three channels are identified using a beam-constrained-mass variable. The shapes of the exclusive cross sections show oscillatory behavior with several maxima and minima. The results are obtained using data collected by the Belle experiment at the KEKB asymmetric-energy ee collider.[graphic not available: see fulltext
Measurements of the Branching Fractions , and
No full textInternational audienceUsing the data sample of 711 fb-1 of ϒ(4S) on-resonance data taken by the Belle detector at the KEKB asymmetric-energy electron-positron collider, we present the first measurements of branching fractions of the decays B-→Λ¯c-Ξc′0, B-→Λ¯c-Ξc(2645)0, and B-→Λ¯c-Ξc(2790)0. The signal yields for these decays are extracted from the recoil mass spectrum of the system recoiling against Λ¯c- baryons in selected B- candidates. The branching fraction of B-→Λ¯c-Ξc(2790)0 is measured to be (1.1±0.4±0.2)×10-3, where the first uncertainty is statistical and the second is systematic. The 90% credibility level upper limits on B(B-→Λ¯c-Ξc′0) and B(B-→Λ¯c-Ξc(2645)0) are determined to be 6.5×10-4 and 7.9×10-4, respectively
Measurements of the branching fractions B (B ̄0 → D∗+ π-) and B(B ̄0 →D∗+ K-) and tests of QCD factorization
No full textUsing (771.6±10.6)×106 BB ̄ meson pairs recorded by the Belle experiment at the KEKB e+e- collider, we report the branching fractions B(B ̄0→D∗+π-)=(2.62±0.02±0.09)×10-3 and B(B ̄0→D∗+K-)=(2.22±0.06±0.08)×10-4; the quoted uncertainties are statistical and systematic, respectively. A measurement of the ratio of these branching fractions is also presented, RK/π=B(B ̄→D∗+K-)/B(B ̄→D∗+π-)=(8.41±0.24±0.13)×10-2, where systematic uncertainties due to the D∗+ meson reconstruction cancel out. Furthermore, we report a new QCD factorization test based on the measured ratios for B ̄→D∗+h- and B ̄→D∗+l-ν decays at squared momentum transfer values equivalent to the mass of the h=π or K hadron. The parameters |a1(h)| are measured to be |a1(π)|=0.884±0.004±0.003±0.016 and |a1(K)|=0.913±0.019±0.008±0.013, where the last uncertainties account for all external inputs. These values are approximately 15% lower than those expected from theoretical predictions. Subsequently, flavor SU(3) symmetry is tested by measuring the ratios for pions and kaons, |a1(K)|2/|a1(π)|2=1.066±0.042±0.018±0.023, as well as for different particle species. The ratio is consistent with unity and therefore no evidence for SU(3) symmetry breaking effects is found at the 5% precision level
Study of B-+/-,B-0 -> J/psi(K+K-K +/-,0) and search for B-0 -> J/psi phi at BABAR
No full textWe study the rare B meson decays B-+/-,B-0 -> J/psi(K+K-K +/-,0), B-+/-,B-0 -> J/psi phi K-+/-,K-0, and search for B-0 -> J/psi phi, using 469 x 10(6) B (B) over bar events collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II e(+)e(-) asymmetric energy collider. We present new measurements of branching fractions and a study of the J/psi phi mass distribution in search of new charmonium-like states. In addition, we search for the decay B-0 -> J/psi phi and find no evidence of a signal
Study of CP Asymmetry in B-0-(B)over-bar(0) Mixing with Inclusive Dilepton Events
No full textWe present a measurement of the asymmetry A(CP) between same- sign inclusive dilepton samples l(+) l(+) and l(-) l(-) ( l = e, mu) from semileptonic B decays in Y(4S) -> B (B) over bar events, using the complete data set recorded by the BABAR experiment near the Y(4S) resonance, corresponding to 471 x 10(6) B (B) over bar pairs. The asymmetry A(CP) allows comparison between the mixing probabilities P((B) over bar (0) -> B-0) and P(B-0 -> (B) over bar (0)) and therefore probes CP and T violation. The result, A(CP) = [-3.9 +/- 3.5(stat) +/- 1.9(syst)] x 10(-3), is consistent with the standard model expectation
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