LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., & Ruiz Valls, P. (2014). Measurement of resonant and CP components in (B)over-bar(s)(0) -> J/psi pi(+)pi(-) decays. Phys. Rev. D, 89(9), 092006–21pp.
Abstract: Structure of the decay B0s. J=.pp- is studied using data corresponding to 3 fb- 1 of integrated luminosity from pp collisions produced by the LHC and collected by the LHCb detector. Five interfering pp- states are required to describe the decay: F-0(980), F-0(1500), F-0(1790), F-2 (1270) and F-2(1525) An alternative model including these states and a nonresonant J=.pp- component also provides a good description of the data. Based on the different transversity components measured for the spin- 2 intermediate states, the final state is found to be compatible with being entirely CP odd. The CP- even part is found to be < 2.3% at a 95% confidence level. The f 0d500 state is not observed, allowing a limit to be set on the absolute value of the mixing angle with the f 0d980 of < 7.7 at a 90% confidence level, consistent with a tetraquark interpretation of the f(0)(980) substructure.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2014). Dalitz plot analysis of eta(c) -> K+K-eta and eta(c) -> K+K-pi(0) in two-photon interactions. Phys. Rev. D, 89(11), 112004–16pp.
Abstract: We study the processes gamma gamma -> K+K-eta and gamma gamma -> K+K-pi(0) using a data sample of 519 fb(-1) recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e(+)e(-) collider at center-of-mass energies at and near the Upsilon(nS) (n = 2, 3, 4) resonances. We observe eta(c) -> K+K-pi(0) and eta(c) -> K+K-eta decays, measure their relative branching fraction, and perform a Dalitz plot analysis for each decay. We observe the K*(0)(1430) -> K eta decay and measure its branching fraction relative to the K pi decay mode to be R(K*(0)(1430)) = B(K*(0)(1430)-> K eta)/B(K*(0)(1430)-> K pi) = 0.092 +/- 0.025(- 0.025)(+0.010). The eta(c) -> K+K-eta and K*(0)(1430) -> K eta results correspond to the first observations of these channels. The data also show evidence for eta(c)(2S) -> K+K-pi(0) and first evidence for eta(c)(2S) -> K+K-eta.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2014). Study of the reaction e(+)e(-) -> psi(2S)pi(+)pi(-) via initial-state radiation at BABAR. Phys. Rev. D, 89(11), 111103–8pp.
Abstract: We study the process e(+)e(-) -> psi(2S)pi(+)pi(-) with initial-state-radiation events produced at the PEP-II asymmetric-energy collider. The data were recorded with the BABAR detector at center-of-mass energies at and near the (nS) (n = 2, 3, 4) resonances and correspond to an integrated luminosity of 520 fb(-1). We investigate the psi(2S)pi(+)pi(-) mass distribution from 3.95 to 5.95 GeV/c(2), and measure the center-of-mass energy dependence of the associated e(+)e(-) -> psi(2S)pi(+)pi(-) cross section. The mass distribution exhibits evidence of two resonant structures. A fit to the psi(2S)pi(+)pi(-) mass distribution corresponding to the decay mode psi(2S) -> J/psi pi(+)pi(-) yields a mass value of 4340 +/- 16 (stat) +/- 9 (syst) MeV/c(2) and a width of 94 +/- 32 (stat) +/- 13 (syst) MeV for the first resonance, and for the second a mass value of 4669 +/- 21 (stat) +/- 3 (syst) MeV/c(2) and a width of 104 +/- 48 (stat) +/- 10 (syst) MeV. In addition, we show the pi(+)pi(-) mass distributions for these resonant regions.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2014). Antideuteron production in Upsilon(nS) decays and in e(+)e(-) -> q(q) over bar at root s approximate to 10.58 GeV. Phys. Rev. D, 89(11), 111102–8pp.
Abstract: We present measurements of the inclusive production of antideuterons in e(+)e(-) annihilation into hadrons at approximate to 10.58 GeV center-of-mass energy and in Upsilon(1S, 2S, 3S) decays. The results are obtained using data collected by the BABAR detector at the PEP-II electron-positron collider. Assuming a fireball spectral shape for the emitted antideuteron momentum, we find B(Upsilon(1S) -> (d) over barX) = (2.81 +/- 0.49(stat)-(+0.20)(0.24)(syst)) x 10(-5), B(Upsilon(2S) -> (d) over barX) = (2.64 +/- 0.11(stat)(-0.21)(+0.26)(syst)) x 10(-5), B(Upsilon(3S) -> (d) over barX) = (2.33 +/- 0.15(stat)(-0.28)(+0.31)(syst)) x 10(-5), and sigma(e(+)e(-) -> (d) over barX) = (9.63 +/- 0.41(stat)(-1.01)(+1.17)(syst) fb.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2014). Evidence for the baryonic decay (B)over-bar(0) -> D-0 Lambda(Lambda)over-bar. Phys. Rev. D, 89(11), 112002–9pp.
Abstract: Evidence is presented for the baryonic B meson decay (B) over bar (0) -> (B) over bar (0)Lambda(Lambda) over bar based on a data sample of 471 x 10(6) B (B) over bar pairs collected with the BABAR detector at the PEP-II asymmetric e(+)e(-) collider located at the SLAC National Accelerator Laboratory. The branching fraction is determined to be B((B) over bar (0) -> (B) over bar (0)Lambda(Lambda) over bar) = (9.8(-2.6)(+2.9) +/- 1.9) x 10(-6), corresponding to a significance of 3.4 standard deviations including additive systematic uncertainties. A search for the related baryonic B meson decay (B) over bar (0) -> D-0 Sigma(0)(Lambda) over bar (0) with Sigma(0) -> Lambda gamma is performed and an upper limit B((B)over bar>(0) -> D-0 Sigma(0)(Lambda) over bar + (B)over bar>(0) -> D-0 Lambda(Sigma) over bar (0)) < 3.1 x 10(-5) is determined at 90% confidence level.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Measurement of the resonant and CP components in (B)over-bar(0) -> J/psi pi(+)pi(-) decays. Phys. Rev. D, 90(1), 012003–21pp.
Abstract: The resonant structure of the reaction (B) over bar (0) --> J/psi pi(+)pi(-) is studied using data from 3 fb(-1) of integrated luminosity collected by the LHCb experiment, one third at 7 TeV center-of-mass energy and the remainder at 8 TeV. The invariant mass of the pi(+)pi(-) pair and three decay angular distributions are used to determine the fractions of the resonant and nonresonant components. Six interfering pi(+)pi(-) states, rho(770), f(0)(500), f(2)(1270), rho(1450), omega(782) and rho(1700), are required to give a good description of invariant mass spectra and decay angular distributions. The positive and negative charge parity fractions of each of the resonant final states are determined. The f(0)(980) meson is not seen and the upper limit on its presence, compared with the observed f(0)(500) rate, is inconsistent with a model where these scalar mesons are formed from two quarks and two antiquarks (tetraquarks) at the eight standard deviation level. In the q (q) over bar model, the absolute value of the mixing angle between the f(0)(980) and the f(0)(500) scalar mesons is limited to be less than 17 degrees at 90% confidence level.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Measurement of the ratio of B-c(+) branching fractions to J/psi pi(+) and J/psi mu(+)nu(mu) final states. Phys. Rev. D, 90(3), 032009–11pp.
Abstract: The first measurement that relates semileptonic and hadronic decay rates of the B-c(+) meson is performed using proton-proton collision data corresponding to 1.0 fb(-1) of integrated luminosity collected with the LHCb detector. The measured value of the ratio of branching fractions, B(B-c(+) -> J/psi pi(+))/B(B-c(+) -> J/psi mu(+)nu(mu)) = 0.0469 +/- 0.0028(stat) +/- 0.0046(syst), is at the lower end of available theoretical predictions.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Measurement of CP violation in B-s(0) ->Phi Phi decays. Phys. Rev. D, 90(5), 052011–17pp.
Abstract: A measurement of the decay time-dependent CP-violating asymmetry in B-s(0) -> phi phi decays is presented, along with measurements of the T-odd triple-product asymmetries. In this decay channel, the CP-violating weak phase arises from the interference between B-s(0) -(B) over bar (0)(s) mixing and the loop-induced decay amplitude. Using a sample of proton-proton collision data corresponding to an integrated luminosity of 3.0 fb(-1) collected with the LHCb detector, a signal yield of approximately 4000 B-s(0) -> phi phi decays is obtained. The CP-violating phase is measured to be phi(s) = -0.17 +/- 0.15(stat) +/- 0.03(syst) rad. The triple-product asymmetries are measured to be A(U) = -0.003 +/- 0.017(stat) +/- 0.006(syst) and A(V) = -0.017 +/- 0.017(stat) +/- 0.006(syst). Results are consistent with the hypothesis of CP conservation.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2014). Measurement of Collins asymmetries in inclusive production of charged pion pairs in e(+)e(-) annihilation at BABAR. Phys. Rev. D, 90(5), 052003–26pp.
Abstract: We present measurements of Collins asymmetries in the inclusive process e(+)e(-) -> pi pi X, where p stands for charged pions, at a center-of-mass energy of 10.6 GeV. We use a data sample of 468 fb(-1) collected by the BABAR experiment at the PEP-II B factory at SLAC, and consider pairs of charged pions produced in opposite hemispheres of hadronic events. We observe clear asymmetries in the distributions of the azimuthal angles in two distinct reference frames. We study the dependence of the asymmetry on several kinematic variables, finding that it increases with increasing pion momentum and momentum transverse to the analysis axis, and with increasing angle between the thrust and beam axis.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2014). Dalitz plot analysis of B-s(0) -> (D)over-bar(0)K(-)pi(+) decays. Phys. Rev. D, 90(7), 072003–29pp.
Abstract: The resonant substructure of B-s(0) -> (D) over bar K-0(-)pi(+) decays is studied with the Dalitz plot analysis technique. The study is based on a data sample corresponding to an integrated luminosity of 3.0 fb(-1) of pp collision data recorded by LHCb. A structure at m((D) over bar K-0(-)) approximate to 2.86 GeV/c(2) is found to be an admixture of spin-1 and spin-3 resonances. The masses and widths of these states and of the D-s2*(2573)(-) meson are measured, as are the complex amplitudes and fit fractions for all the (D) over bar K-0(-) and K-pi(-) components included in the amplitude model. In addition, the D-s2*(2573)(-) resonance is confirmed to be spin 2.
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