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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2012). Search for resonances decaying to eta(c)pi(+) pi(-) in two-photon interactions. Phys. Rev. D, 86(9), 092005–10pp.
Abstract: We report a study of the process gamma gamma -> X -> eta(c)pi(+)pi(-) , where X stands for one of the resonances chi(c2)(1P), eta(c)(2S), X(3872), X(3915), or chi(c2)(2P). The analysis is performed with a data sample of 473.9 fb(-1) collected with the BABAR detector at the PEP-II asymmetric-energy electron-positron collider. We do not observe a significant signal for any channel, and calculate 90% confidence-level upper limits on the products of branching fractions and two-photon widths Gamma B-x ->gamma gamma(X -> eta(c)pi(+) pi(-)): 15.7 eV for chi(c2)(1P), 133 eV for eta(c)(2S), 11.1 eV for X(3872) (assuming it to be a spin-2 state), 16 eV for X(3915) (assuming it to be a spin-2 state), and 18 eV for chi(c2)(2P). We also report upprt limits on the rations of branching fractions B(eta(c)(2S) -> eta(c)pi(+) pi(-))/B(eta(c)(2S) -> (KSK+)-K-0 pi(-)) < 10.0 and B(chi(c2)(1P) -> eta(c)pi(+) pi(-))/B(chi(c2)(1P) -> (KSK+)-K-0 pi(-)) < 32.9 at the 90% confidence level.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2012). Precise measurement of the e(+)e(-) -> pi(+)pi(-)(gamma) cross section with the initial-state radiation method at BABAR. Phys. Rev. D, 86(3), 032013–49pp.
Abstract: A precise measurement of the cross section of the process e(+)e(-) -> pi(+)pi(-) (gamma) from threshold to an energy of 3 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 ISR luminosity is determined from a study of the leptonic process e(+)e(-) -> mu(+)mu(-) (gamma)gamma(ISR), which is found to agree with the next-to-leading-order QED prediction to within 1.1%. The cross section for the process e(+)e(-) -> pi(+)pi(-) (gamma) is obtained with a systematic uncertainty of 0.5% in the dominant rho resonance region. The leading-order hadronic contribution to the muon magnetic anomaly calculated using the measured pi pi cross section from threshold to 1.8 GeV is (514.1 +/- 2.2(stat) +/- 3.1(sys)) x 10(-10).
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2012). Measurement of branching fractions and rate asymmetries in the rare decays B -> K((*))l(+)l(-). Phys. Rev. D, 86(3), 032012–15pp.
Abstract: In a sample of 471 x 10(6) B (B) over bar events collected with the BABAR detector at the PEP-II e(+)e(-) collider we study the rare decays B -> K((*))l(+)l(-), where l(+)l(-) is either e(+)e(-) or mu(+)mu(-). We report results on partial branching fractions and isospin asymmetries in seven bins of dilepton mass-squared. We further present CP and lepton-flavor asymmetries for dilepton masses below and above the J/psi resonance. We find no evidence for CP or lepton-flavor violation. The partial branching fractions and isospin asymmetries are consistent with the Standard Model predictions and with results from other experiments.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2012). Search for the decay modes B-+/- -> h(+/-)tau l. Phys. Rev. D, 86(1), 012004–14pp.
Abstract: We present a search for the lepton flavor violating decay modes B-+/- -> h(+/-)tau l (h = K, pi; l = e, mu) using the BABAR data sample, which corresponds to 472 x 10(6) B (B) over bar pairs. The search uses events where one B meson is fully reconstructed in one of several hadronic final states. Using the momenta of the reconstructed B, h, and l candidates, we are able to fully determine the tau four-momentum. The resulting tau candidate mass is our main discriminant against combinatorial background. We see no evidence for B-+/- -> h(+/-)tau l decays and set a 90% confidence level upper limit on each branching fraction at the level of a few times 10(-5).
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2012). Study of CP violation in Dalitz-plot analyses of B-0 -> K+ K- K-s(0), B+ -> K+ K- K+, and B+ -> (KsKsK+)-K-0-K-0. Phys. Rev. D, 85(11), 112010–31pp.
Abstract: We perform amplitude analyses of the decays B-0 -> K+ K- K-s(0), B+ -> K+ K- K+, and B+ -> K-s(0) K-s(0) K+, and measure CP-violating parameters and partial branching fractions. The results are based on a data sample of approximately 470 x 10(6) B (B) over bar decays, collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory. For B+ -> K+ K- K+, we find a direct CP asymmetry in B+ -> phi(1020)K+ of A(CP) = (12.8 +/- 4.4 +/- 1.3)%, which differs from zero by 2.8 sigma. For B-0 -> K+ K- K-s(0), we measure the CP-violating phase ss(eff)(phi(1020)K-s(0)) = (21 +/- 6 +/- 2)degrees. For B+ -> K-s(0) K-s(0) K+, we measure an overall direct CP asymmetry of A(CP) = (4(-5)(+4) +/- 2)%. We also perform an angular-moment analysis of the three channels and determine that the f(X()1500) state can be described well by the sum of the resonances f(0)(1500), f(2)'(1525), and f(0)(1710).
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