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BABAR Collaboration(Lees, J. P. et al), Azzolini, V., Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Limits on tau lepton-flavor violating decays into three charged leptons. Phys. Rev. D, 81(11), 111101–8pp.
Abstract: A search for the neutrinoless, lepton-flavor violating decay of the tau lepton into three charged leptons has been performed using an integrated luminosity of 468 fb(-1) collected with the BABAR detector at the PEP-II collider. In all six decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range (1.8-3.3) x 10(-8) at 90% confidence level.
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BABAR Collaboration(Lees, J. P. et al), Azzolini, V., Lopez-March, N., Martinez-Vidal, F., Milanes, D. A., & Oyanguren, A. (2010). Measurement of the gamma gamma* -> eta c transition form factor. Phys. Rev. D, 81(5), 052010–18pp.
Abstract: We study the reaction e(+)e(-) -> e(+)e(-) eta(c), eta(c) -> KSK +/-pi(-/+) and obtain eta(c) mass and width values 2982.2 +/- 0.4 +/- 1.6 MeV/c(2) and 31.7 +/- 1.2 +/- 0.8 MeV, respectively. We find Gamma(eta(c) -> gamma gamma)B(eta(c) -> KK pi) = 0.374 +/- 0.009 +/- 0.031 keV, and measure the gamma gamma* -> eta(c) transition form factor in the momentum transfer range from 2 to 50 GeV2. The analysis is based on 469 fb(-1) of integrated luminosity collected at PEP-II with the BABAR detector at e(+)e(-) center-of-mass energies near 10.6 GeV.
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BABAR Collaboration(Lees, J. P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Measurement of the mass and width of the D_s1 (2536)+ meson. Phys. Rev. D, 83(7), 072003–14pp.
Abstract: The decay width and mass of the D-s1(2536)(+) meson are measured via the decay channel D-s1(+) -> (D*+KS0) using 385 fb(-1) of data recorded with the BABAR detector in the vicinity of the Gamma(4S) resonance at the PEP-II asymmetric-energy electron-positron collider. The result for the decay width is Gamma(D-s1(+)) = 92 +/- 0.03(stat.) +/- 0.04(syst.) MeV. For the mass, a value of m(D-s1(+)) = 2535.08 +/- 0.01(stat.) +/- 0.15(syst.) MeV/c(2) is obtained. The mass difference between the D-s1(+) and the D*+ is measured to be m(D-s1(+)) – m(D*+) = 524.83 +/- 0.01(stat.) +/- 0.04(syst.) MeV/c(2), representing a significant improvement compared to the current world average. The unnatural spin-parity assignment for the D-s1(+) meson is confirmed.
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BABAR Collaboration(Lees, J. P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Amplitude analysis of B0 -> K+ pi- pi0 and evidence of direct CP violation in B -> K * pi decays. Phys. Rev. D, 83(11), 112010–21pp.
Abstract: We analyze the decay B-0 -> K+ pi(-) pi(0) with a sample of 4.54 x 10(8) B (B) over bar events collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, and extract the complex amplitudes of seven interfering resonances over the Dalitz plot. These results are combined with amplitudes measured in B-0 -> K-S(0)pi(+)pi(-) decays to construct isospin amplitudes from B-0 -> K* pi and B-0 -> rho K decays. We measure the phase of the isospin amplitude Phi(3/2), useful in constraining the Cabibbo-Kobayashi-Maskawa unitarity triangle angle gamma and evaluate a CP rate asymmetry sum rule sensitive to the presence of new physics operators. We measure direct CP violation in B-0 -> K*(+) pi(-) decays at the level of 3 sigma when measurements from both B-0 -> K+ pi(-) pi(0) and B-0 -> K-S(0) pi(+) pi(-) decays are combined.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2011). Observation of the baryonic B decay (B)over-bar(0) -> Lambda(+)(c)(Lambda)over-barK(-). Phys. Rev. D, 84(7), 071102–7pp.
Abstract: We report the observation of the baryonic B decay (B) over bar (0) -> Lambda(+)(c)Lambda K(-) with a significance larger than 7 standard deviations based on 471 x 10(6) B (B) over bar pairs collected with the BABAR detector at the PEP-II storage ring at SLAC. We measure the branching fraction for the decay (B) over bar (0) -> Lambda(+)(c)Lambda K(-) to be (3.8 +/- 0.8(stat) +/- 0.2(sys) +/- 1.0(Lambda c)(+)) x 10(-5). The uncertainties are statistical, systematic, and due to the uncertainty in the Lambda(+)(c) branching fraction. We find that the Lambda(+)(c)K(-) invariant-mass distribution shows an enhancement above 3.5 GeV/c(2).
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