Recent astrophysical and terrestrial experiments have motivated the proposal of a dark sector with GeV-scale gauge boson force carriers and new Higgs bosons. We present a search for a dark Higgs ...boson using 516 fb(-1) of data collected with the BABAR detector. We do not observe a significant signal and we set 90% confidence level upper limits on the product of the standard model-dark-sector mixing angle and the dark-sector coupling constant.
Evidence for the decay X ( 3872 ) → J / ψ ω Poireau, V.; Hooberman, B.; Kerth, L. T. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
07/2010, Letnik:
82, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We present a study of the decays B^{0,+} --> J/psi pi^+ pi^- pi^0 K^{0,+}, using 467 10^6 BBbar pairs recorded with the BABAR detector. We present evidence for the decay mode X(3872) --> J/psi omega, ...with product branching fractions B(B^+ --> X(3872)K^+) B(X(3872) --> J/psi omega) =0.6\pm0.2\stat \pm 0.1\syst 10^{-5}, and B(B^0 --> X(3872)K^0) B(X(3872) --> J/psi omega) =0.6\pm0.3\stat \pm 0.1\syst 10^{-5}. A detailed study of the pi^+ pi^- pi^0 mass distribution from X(3872) decay favors a negative-parity assignment.
We have performed a search for the η b ( 1 S ) meson in the radiative decay of the Υ ( 2 S ) resonance using a sample of 91.6 × 10 6 Υ ( 2 S ) events recorded with the BABAR detector at the PEP-II B ...factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at E γ = 609.3 + 4.6 − 4.5 ( stat ) ± 1.9 ( syst ) MeV , corresponding to an η b ( 1 S ) mass of 9394.2 + 4.8 − 4.9 ( stat ) ± 2.0 ( syst ) MeV / c 2 . The branching fraction for the decay Υ ( 2 S ) → γ η b ( 1 S ) is determined to be 3.9 ± 1.1 ( stat ) + 1.1 − 0.9 ( syst ) × 10 − 4 . We find the ratio of branching fractions B Υ ( 2 S ) → γ η b ( 1 S ) / B Υ ( 3 S ) → γ η b ( 1 S ) = 0.82 ± 0.24 ( stat ) + 0.20 − 0.19 ( syst ) .
A precise measurement of the cross section for the process e + e − → K + K − ( γ ) from threshold to an energy of 5 GeV is obtained with the initial-state radiation (ISR) method using 232 fb − 1 ...of data collected with the BABAR detector at e + e − center-of-mass energies near 10.6 GeV. The measurement uses the effective ISR luminosity determined from the e + e − → μ + μ − ( γ ) γ ISR process with the same data set. The corresponding lowest-order contribution to the hadronic vacuum polarization term in the muon magnetic anomaly is found to be a K K , LO μ = ( 22.93 ± 0.18 stat ± 0.22 syst ) × 10 − 10 . The charged kaon form factor is extracted and compared to previous results. Its magnitude at large energy significantly exceeds the asymptotic QCD prediction, while the measured slope is consistent with the prediction.
Leptonic B decays at BaBar Monorchio, D
Journal of physics. Conference series,
05/2008, Letnik:
110, Številka:
5
Journal Article
Recenzirano
Odprti dostop
We present a selection of recent results from studies of rare and leptonic B decays, based on a sample of 383 million of B pairs, corresponding to an integrated luminosity of 346 fb-1, which were ...recorded with the BaBar detector at the PEP-II asymmetric-energy e+e−storage ring.
We present updated results on time-dependent CP asymmetries in fully reconstructed B0->D(*)+-pi-+ and B0->D+-rho-+ decays in approximately 232 million Y(4S)->BBbar events collected with the BaBar ...detector at the PEP-II asymmetric-energy B factory at SLAC. From a time-dependent maximum likelihood fit we obtain for the parameters related to the CP violation angle 2beta+gamma: a^{D\pi} = -0.010 +/- 0.023 +/- 0.007, c_{\rm lep}^{D\pi} = -0.033 +/- 0.042 +/- 0.012, a^{D^*\pi} = -0.040 +/- 0.023 +/- 0.010, c_{\rm lep}^{D^*\pi} = 0.049 +/- 0.042 +/- 0.015, a^{D\rho} = -0.024 +/- 0.031 +/- 0.009, c_{\rm lep}^{D\rho} = -0.098 +/- 0.055 +/- 0.018, where the first error is statistical and the second is systematic. Using other measurements and theoretical assumptions, we interpret the results in terms of the angles of the Cabibbo-Kobayashi-Maskawa unitarity triangle and find |sin(2beta+gamma)| > 0.64 (0.40) at 68% (90%) confidence level.
We report the measurement of the Cabibbo-Kobayashi-Maskawa CP-violating angle γ through a Dalitz plot analysis of neutral D-meson decays to K(S)(0) π+ π- and K(S)(0) K+ K- produced in the processes ...B∓ → DK∓, B∓ D* K∓ with D* → Dπ(0), Dγ, and B∓ → DK*∓ with K*∓ → K(S)(0) π∓, using 468 million BB pairs collected by the BABAR detector at the PEP-II asymmetric-energy e+ e- collider at SLAC. We measure γ = (68 ± 14 ± 4 ± 3)° (modulo 180°), where the first error is statistical, the second is the experimental systematic uncertainty, and the third reflects the uncertainty in the description of the neutral D decay amplitudes. This result is inconsistent with γ = 0 (no direct CP violation) with a significance of 3.5 standard deviations.
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