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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2011). Study of Y(3S, 2S) -> eta Y(1S) and Y(3S, 2S) -> pi(+) pi(-) Y(1S) hadronic transitions. Phys. Rev. D, 84(9), 092003–8pp.
Abstract: We study the Y(3S, 2S) -> eta Y(1S) and Y (3S,2S) -> pi(+)pi(-) transitions with 122 x 10(6) x Y(3S) and 100 x 10(6) Y (2S) mesons collected by the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider. We measure B[Y(2S) -> eta Y(1S)] = (2.39 +/- 0.31 (stat) +/- 0.14(syst)) x 10(-4) and Gamma[Y(2S) -> eta Y(1S)]/Gamma[Y(2S) ->pi(+)pi(-)(1S)] – (2.39 +/- 0.31(stat) +/- 0.14(syst)) x 10(-3). We find no evidence for Y(3S) -> eta Y (1S) and obtain B[Y(3S) -> eta Y(1S)] < 1.0 x 10(-4) and Gamma[Y (3S) -> eta Y(1S)/Gamma[Y(3S) -> pi(+)pi(-) Y(1S)] < 2.3 x 10(-3) as upper limits at the 90% confidence level. We also provide improved measurements of the Y(S) – Y(1S) and Y(3S) – Y (1S) mass differences, 562.170 +/- 0.007(stat) +/- 0.088(syst). MeV/c(2) and 893.813 +/- 0: 015(stat) +/- 0.107(syst.) MeV/c(2), respectively.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2012). Measurement of the semileptonic branching fraction of the B(s) meson. Phys. Rev. D, 85(1), 011101–9pp.
Abstract: We report a measurement of the inclusive semileptonic branching fraction of the B(s) meson using data collected with the BABAR detector in the center-of-mass energy region above the Y(4S) resonance. We use the inclusive yield of phi mesons and the phi yield in association with a high-momentum lepton to perform a simultaneous measurement of the semileptonic branching fraction and the production rate of B(s) mesons relative to all B mesons as a function of center-of-mass energy. The inclusive semileptonic branching fraction of the B(s) meson is determined to be B(B(s) -> l nu X) = 9.5(-2.0)(+2.5)(stat)(-1.9)(+1.1)(syst)% where l indicates the average of e and mu.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2012). Search for the Z(1)(4050)(+) and Z(2)(4250)(+) states in (B)over-bar(0) -> chi K-c1(-)pi(+) and B+ -> chi K-c1(S)0 pi(+). Phys. Rev. D, 85(5), 052003–12pp.
Abstract: We search for the Z(1)(4050)(+) and Z(2)(4250)(+) states, reported by the Belle Collaboration, decaying to chi(c1)pi(+) in the decays (B) over bar (0) -> chi K-c1(-)pi(+) and B+ -> chi K-c1(S)0 pi(+) where chi(c1) -> J/psi gamma. The data were collected with the BABAR detector at the SLAC PEP-II asymmetric-energy e(+)e(-) collider operating at center-of-mass energy 10.58 GeV, and correspond to an integrated luminosity of 429 fb(-1). In this analysis, we model the background-subtracted, efficiency-corrected chi(c1)pi(+) mass distribution using the K pi mass distribution and the corresponding normalized K pi Legendre-polynomial moments, and then test the need for the inclusion of resonant structures in the description of the chi(c1)pi(+) mass distribution. No evidence is found for the Z(1)(4050)(+) and Z(2)(4250)(+) resonances, and 90% confidence level upper limits on the branching fractions are reported for the corresponding B-meson decay modes.
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BABAR Collaboration(Lees, J. P. et al), Azzolini, V., Martinez-Vidal, F., & Oyanguren, A. (2012). Study of (B)over-bar -> X(u)l(v)over-bar decays in B(B)over-bar events tagged by a fully reconstructed B-meson decay and determination of vertical bar V-ub vertical bar. Phys. Rev. D, 86(3), 032004–23pp.
Abstract: We report measurements of partial branching fractions for inclusive charmless semileptonic B decays (B) over bar -> X(u)l (v) over bar and the determination of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element vertical bar V-ub vertical bar. The analysis is based on a sample of 467 x 10(6) Y(4S) -> B (B) over bar decays recorded with the BABAR detector at the PEP- II e(+)e(-) storage rings. We select events in which the decay of one of the B mesons is fully reconstructed and an electron or a muon signals the semileptonic decay of the other B meson. We measure partial branching fractions Delta B in several restricted regions of phase space and determine the CKM element vertical bar V-ub vertical bar based on different QCD predictions. For decays with a charged lepton momentum p(l)* > 1.0 GeV in the B meson rest frame, we obtain Delta B = (1.80 +/- 0.13(stat) +/- 0.15(sys) +/- 0.02(theo)) x 10(-3) from a fit to the two-dimensional M-X – q(2) distribution. Here, M-X refers to the invariant mass of the final state hadron X and q(2) is the invariant mass squared of the charged lepton and neutrino. From this measurement we extract vertical bar V-ub vertical bar = (4.33 +/- 0.24(exp) +/- 0.15(theo)) x 10(-3) as the arithmetic average of four results obtained from four different QCD predictions of the partial rate. We separately determine partial branching fractions for (B) over bar (0) and B- decays and derive a limit on the isospin breaking in (B) over bar -> X(u)l (v) over bar decays.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2012). Initial-state radiation measurement of the e(+)e(-) -> pi(+)pi(-)pi(+)pi(-) cross section. Phys. Rev. D, 85(11), 112009–17pp.
Abstract: We study the process e(+)e(-) -> pi(+)pi(-)pi(+)pi(-)gamma, with a photon emitted from the initial-state electron or positron, using 454.3 fb(-1) of data collected with the BABAR detector at SLAC, corresponding to approximately 260 000 signal events. We use these data to extract the nonradiative sigma(e(+)e(-) -> pi(+)pi(-)pi(+)pi(-)) cross section in the energy range from 0.6 to 4.5 GeV. The total uncertainty of the cross section measurement in the peak region is less than 3%, higher in precision than the corresponding results obtained from energy scan data.
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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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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). 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). 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). 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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