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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Measurements of branching fractions, polarizations, and direct CP-violation asymmetries in B+ -> rho K-0*(+) and B+ -> f(0)(980)K*(+) decays. Phys. Rev. D, 83(5), 051101–8pp.
Abstract: We present measurements of the branching fractions, longitudinal polarization, and direct CP-violation asymmetries for the decays B+ -> rho K-0*(+) and B+ -> f(0)(980)K*(+) with a sample of (467 +/- 5) x 10(6)B (B) over bar pairs collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at the SLAC National Accelerator Laboratory. We observe B+ -> rho K-0*(+) with a significance of 5: 3 sigma and measure the branching fraction B(B+ -> rho K-0*(+)) = (4.6 +/- 1.0 +/- 0.4) x 10(-6), the longitudinal polarization f(L) = 0.78 +/- 0.12 +/- 0.03, and the CP-violation asymmetry A(CP) = 0.31 +/- 0.13 +/- 0.03. We observe B+ -> f(0)(980)K*(+) and measure the branching fraction B(B+ -> f(0)(980)K*(+)) x B(f(0)(980) -> pi(+)pi(-)) = (4.2 +/- 0.6 +/- 0.3) x 10(-6) and the CP-violation asymmetry A(CP) = 0.15 +/- 0.12 +/- 0.03. The first uncertainty quoted is statistical and the second is systematic.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Measurement of partial branching fractions of inclusive charmless B meson decays to K+, K-0, and pi(+). Phys. Rev. D, 83(3), 031103–8pp.
Abstract: We present measurements of partial branching fractions of B -> K+ X, B -> (KX)-X-0, and B -> pi(+) X, where X denotes any accessible final state above the endpoint for B decays to charmed mesons, specifically for momenta of the candidate hadron greater than 2.34 (2.36) GeV for kaons (pions) in the B rest frame. These measurements are sensitive to potential new-physics particles which could enter the b -> s(d) loop transitions. The analysis is performed on a data sample consisting of 383 X 10(6)B (B) over bar pairs collected with the BABAR detector at the PEP-II e(+)e(-) asymmetric energy collider. We observe the inclusive B -> pi(+) X process, and we set upper limits for B -> K+ X and B -> (KX)-X-0. Our results for these inclusive branching fractions are consistent with those of known exclusive modes, and exclude large enhancements due to sources of new physics.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Analysis of the D+ -> K- pi(+) e(+) nu(e) decay channel. Phys. Rev. D, 83(7), 072001–35pp.
Abstract: Using 347: 5 fb(-1) of data recorded by the BABAR detector at the PEP-II electron-positron collider, 244 x 10(3) signal events for the D+ -> K- pi(+)e(+)nu(e) decay channel are analyzed. This decay mode is dominated by the (K) over bar*(892)(0) contribution. We determine the (K) over bar*(892)(0) parameters: m(K*(892)0) (895.4 +/- 0.2 +/- 0.2) MeV/c(2),Gamma(0)(K*(892)0) (46.5 +/- 0.3 +/- 0.2) MeV/c(2), and the Blatt-Weisskopf parameter r(BW) = 2.1 +/- 0.5 +/- 0.5 (GeV/c)(-1), where the first uncertainty comes from statistics and the second from systematic uncertainties. We also measure the parameters defining the corresponding hadronic form factors at q(2) = 0 (r(V) = V(0)/A(1)(0) = 1.463 +/- 0.031, r(2) = A(2)(0)/A(1)(0) = 0.801 +/- 0.020 +/- 0.020) and the value of the axial-vector pole mass parametrizing the q(2) variation of A(1) and A(2): m(A) (2.63 +/- 0.10 +/- 0.13) GeV/c(2). The S-wave fraction is equal to (5.79 +/- 0.16 +/- 0: 15)%. Other signal components correspond to fractions below 1%. Using the D+ -> K-pi(+)pi(+) channel as a normalization, we measure the D+ semileptonic branching fraction: B(D+ K-pi(+)e(+)nu(e)) (4.00 +/- 0: 03 +/- 0.04 +/- 0.09) x 10(-2), where the third uncertainty comes from external inputs. We then obtain the value of the hadronic form factor A(1) at q(2) 0: A(1)(0) 0.6200 +/- 0.0056 +/- 0.0065 +/- 0.0071. Fixing the P-wave parameters, we measure the phase of the S wave for several values of the K pi mass. These results confirm those obtained with K pi production at small momentum transfer in fixed target experiments.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Dalitz plot analysis of D-s(+) -> K+ K- pi(+). Phys. Rev. D, 83(5), 052001–20pp.
Abstract: We perform a Dalitz plot analysis of about 100 000 D-s(+) decays to K+ K- pi(+) and measure the complex amplitudes of the intermediate resonances which contribute to this decay mode. We also measure the relative branching fractions of D-s(+) -> K+ K+ pi(-) and D-s(+) -> K+ K+ K-. For this analysis we use a 384 fb(-1) data sample, recorded by the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider running at center-of-mass energies near 10.58 GeV.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Searches for the baryon- and lepton-number violating decays B0 -> Lambda_c+ l-, B- --> Lambda l-, and B- --> (Lambda)bar l-. Phys. Rev. D, 83(9), 091101–8pp.
Abstract: Searches for B mesons decaying to final states containing a baryon and a lepton are performed, where the baryon is either Lambda(c) or Lambda and the lepton is a muon or an electron. These decays violate both baryon and lepton number and would be a signature of physics beyond the standard model. No significant signal is observed in any of the decay modes, and upper limits in the range (3.2-520) x 10(-8) are set on the branching fractions at the 90% confidence level.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Search for CP violation in the decay D(+/-) --> K_S pi(+/-). Phys. Rev. D, 83(7), 071103–8pp.
Abstract: We report on a search for CP violation in the decay D-+/- -> K-S(0)pi(+/-) using a data set corresponding to an integrated luminosity of 469 fb(-1) collected with the BABAR detector at the PEP-II asymmetric energy e(+)e(-) storage rings. The CP- violating decay rate asymmetry A(CP) is determined to be (-0.44 +/- 0: 13(stat) +/- 0.10(syst))%, consistent with zero at 2.7 sigma and with the standard model prediction of (-0.332 +/- 0.006)%. This is currently the most precise measurement of this parameter.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Measurement of the gamma gamma* -> eta and gamma gamma* -> eta ' transition form factors. Phys. Rev. D, 84(5), 052001–19pp.
Abstract: We study the reactions e(+)e(-) --> e(+)e(-) eta((')) in the single-tag mode and measure the gamma gamma* --> eta((')) transition form factors in the momentum-transfer range from 4 to 40 GeV(2). 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(del Amo Sanchez, P. et al), Martinez-Vidal, F., & Oyanguren, A. (2016). Time-dependent analysis of B-0 -> K-S(0)pi(-)pi(+) gamma decays and studies of the K+pi(-)pi(+) system in B+ -> K+pi(-)pi(+)gamma decays. Phys. Rev. D, 93(5), 052013–29pp.
Abstract: We measure the time-dependent CP asymmetry in the radiative-penguin decay B-0 -> K-S(0)pi(-)pi(+)gamma, using a sample of 471 x 10(6) Upsilon(4S) -> B (B) over bar events recorded with the BABAR detector at the PEP-II e(+)(e) over tilde (-) storage ring at SLAC. Using events with m(K pi pi) < 1.8 GeV/c(2), we measure the branching fractions of B+ -> K+pi(-)pi(+)gamma and B-0 -> K-S(0)pi(-)pi(+)gamma, the branching fractions of the kaonic resonances decaying to K+pi(-)pi(+)gamma, as well as the overall branching fractions of the B+ -> rho K-0(+.)gamma, B+ -> K*(0)pi(+)gamma. and S-wave B+ -> (K pi)(0)(*0) pi(+)gamma components. For events from the rho mass band, we measure the CP-violating parameters SKS0 pi+pi-gamma = 0.14 +/- 0.25 +/- 0.03 and CKS0 pi+pi-gamma = -0.39 +/- 0.20(-0.02)(+0.003), where the first uncertainties are statistical and the second are systematic. We extract from this measurement the time-dependent CP asymmetry related to the CP eigenstate rho K-0(S)0 and obtain S-KS(0) = -0.18 +/- 0.32(-0.05)(+0.06), which provides information on the photon polarization in the underlying b -> s gamma transition.
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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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