34 research outputs found

    A study of CP violation in B-+/- -> DK +/- and B-+/- -> D pi(+/-) decays with D -> (KSK +/-)-K-0 pi(-/+) final states

    Get PDF
    A first study of CP violation in the decay modes B±[KS0K±π]Dh±B^\pm\to [K^0_{\rm S} K^\pm \pi^\mp]_D h^\pm and B±[KS0Kπ±]Dh±B^\pm\to [K^0_{\rm S} K^\mp \pi^\pm]_D h^\pm, where hh labels a KK or π\pi meson and DD labels a D0D^0 or D0\overline{D}^0 meson, is performed. The analysis uses the LHCb data set collected in pppp collisions, corresponding to an integrated luminosity of 3 fb1^{-1}. The analysis is sensitive to the CP-violating CKM phase γ\gamma through seven observables: one charge asymmetry in each of the four modes and three ratios of the charge-integrated yields. The results are consistent with measurements of γ\gamma using other decay modes

    Studies of beauty baryon decays to D0ph− and Λ+ch− final states

    Get PDF
    Decays of beauty baryons to the D0phD^0 p h^- and Λc+h\Lambda_c^+ h^- final states (where hh indicates a pion or a kaon) are studied using a data sample of pppp collisions, corresponding to an integrated luminosity of 1.0 fb1^{-1}, collected by the LHCb detector. The Cabibbo-suppressed decays Λb0D0pK\Lambda_b^0\to D^0 p K^- and Λb0Λc+K\Lambda_b^0\to \Lambda_c^+ K^- are observed and their branching fractions are measured with respect to the decays Λb0D0pπ\Lambda_b^0\to D^0 p \pi^- and Λb0Λc+π\Lambda_b^0\to \Lambda_c^+ \pi^-. In addition, the first observation is reported of the decay of the neutral beauty-strange baryon Ξb0\Xi_b^0 to the D0pKD^0 p K^- final state, and a measurement of the Ξb0\Xi_b^0 mass is performed. Evidence of the Ξb0Λc+K\Xi_b^0\to \Lambda_c^+ K^- decay is also reported.Decays of beauty baryons to the D0ph− and Λc+h− final states (where h indicates a pion or a kaon) are studied using a data sample of pp collisions, corresponding to an integrated luminosity of 1.0  fb−1, collected by the LHCb detector. The Cabibbo-suppressed decays Λb0→D0pK− and Λb0→Λc+K− are observed, and their branching fractions are measured with respect to the decays Λb0→D0pπ− and Λb0→Λc+π−. In addition, the first observation is reported of the decay of the neutral beauty-strange baryon Ξb0 to the D0pK− final state, and a measurement of the Ξb0 mass is performed. Evidence of the Ξb0→Λc+K− decay is also reported.Decays of beauty baryons to the D0phD^0 p h^- and Λc+h\Lambda_c^+ h^- final states (where hh indicates a pion or a kaon) are studied using a data sample of pppp collisions, corresponding to an integrated luminosity of 1.0 fb1^{-1}, collected by the LHCb detector. The Cabibbo-suppressed decays Λb0D0pK\Lambda_b^0\to D^0 p K^- and Λb0Λc+K\Lambda_b^0\to \Lambda_c^+ K^- are observed and their branching fractions are measured with respect to the decays Λb0D0pπ\Lambda_b^0\to D^0 p \pi^- and Λb0Λc+π\Lambda_b^0\to \Lambda_c^+ \pi^-. In addition, the first observation is reported of the decay of the neutral beauty-strange baryon Ξb0\Xi_b^0 to the D0pKD^0 p K^- final state, and a measurement of the Ξb0\Xi_b^0 mass is performed. Evidence of the Ξb0Λc+K\Xi_b^0\to \Lambda_c^+ K^- decay is also reported

    Study of forward Z + jet production in pp collisions at √s=7 TeV

    Get PDF
    A measurement of the Z(μ+μ)Z(\rightarrow\mu^+\mu^-)+jet production cross-section in pppp collisions at a centre-of-mass energy s=7\sqrt{s} = 7 TeV is presented. The analysis is based on an integrated luminosity of 1.0fb11.0\,\text{fb}^{-1} recorded by the LHCb experiment. Results are shown with two jet transverse momentum thresholds, 10 and 20 GeV, for both the overall cross-section within the fiducial volume, and for six differential cross-section measurements. The fiducial volume requires that both the jet and the muons from the Z boson decay are produced in the forward direction (2.0<η<4.52.0<\eta<4.5). The results show good agreement with theoretical predictions at the second-order expansion in the coupling of the strong interaction.A measurement of the Z(μ+μ)Z(\rightarrow\mu^+\mu^-)+jet production cross-section in pppp collisions at a centre-of-mass energy s=7\sqrt{s} = 7 TeV is presented. The analysis is based on an integrated luminosity of 1.0fb11.0\,\text{fb}^{-1} recorded by the LHCb experiment. Results are shown with two jet transverse momentum thresholds, 10 and 20 GeV, for both the overall cross-section within the fiducial volume, and for six differential cross-section measurements. The fiducial volume requires that both the jet and the muons from the Z boson decay are produced in the forward direction (2.0<η<4.52.0<\eta<4.5). The results show good agreement with theoretical predictions at the second-order expansion in the coupling of the strong interaction

    Measurement of Upsilon production in collisions at root s=2.76 TeV

    Get PDF
    The production of Υ(1S)\Upsilon(1S), Υ(2S)\Upsilon(2S) and Υ(3S)\Upsilon(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3 pb1pb^{-1} collected in proton-proton collisions at a centre-of-mass energy of s=2.76\sqrt{s}=2.76 TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the Υ\Upsilon transverse momentum and rapidity, over the ranges $p_{\rm T} Upsilon(1S) X) x B(Upsilon(1S) -> mu+mu-) = 1.111 +/- 0.043 +/- 0.044 nb, sigma(pp -> Upsilon(2S) X) x B(Upsilon(2S) -> mu+mu-) = 0.264 +/- 0.023 +/- 0.011 nb, sigma(pp -> Upsilon(3S) X) x B(Upsilon(3S) -> mu+mu-) = 0.159 +/- 0.020 +/- 0.007 nb, where the first uncertainty is statistical and the second systematic

    Preparação de LiNbO3 e LiNbO3:Eu3+ pelo método dos precursores poliméricos

    No full text
    The ferroelectric compound LiNbO3 was prepared by the polymeric precursors method in the polycrystalline form containing different concentrations of Eu3+. The compounds were characterized by X-ray diffraction, vibrational and electronic spectroscopy. Electronic spectroscopy was shown to be sensitive to small concentrations of contaminating phases allowing a good control of the compound purity. The presence of Eu3+ ions leads to the formation of the LiNb3O8 phase in the range of 500 to 800 degreesC. Above this temperature range LiNbO3 and tetragonal (T') EuNbO4 were obtained

    Preparation of LiNbO3 and LiNbO3:Eu3+ by the polymeric precursors method

    Get PDF
    The ferroelectric compound LiNbO3 was prepared by the polymeric precursors method in the polycrystalline form containing different concentrations of Eu3+. The compounds were characterized by X-ray diffraction, vibrational and electronic spectroscopy. Electronic spectroscopy was shown to be sensitive to small concentrations of contaminating phases allowing a good control of the compound purity. The presence of Eu3+ ions leads to the formation of the LiNb3O8 phase in the range of 500 to 800 &deg;C. Above this temperature range LiNbO3 and tetragonal (T') EuNbO4 were obtained.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Estadual Paulista Instituto de QuímicaUniversidade Federal de São Carlos (UFSCar) Departamento de Engenharia de MateriaisUniversidade Federal de São Carlos (UFSCar) Departamento de FísicaUniversidade Estadual Paulista Instituto de Químic

    Evidence for the decay Bc+J/ψ3π+2πB_c^+ \rightarrow J/\psi 3\pi^+ 2\pi^-

    No full text
    Evidence is presented for the decay Bc+J/ψ3π+2πB_c+\rightarrow J/\psi 3\pi^+2\pi^- using proton-proton collision data, corresponding to an integrated luminosity of 3fb1^{-1}, collected with the LHCb detector. A signal yield of 32±832\pm8 decays is found with a significance of 4.5 standard deviations. The ratio of the branching fraction of the Bc+J/ψ3π+2πB_c^+\rightarrow J/\psi 3\pi^+ 2\pi^- decay to that of the Bc+J/ψπ+B_c^+ \rightarrow J/\psi \pi^+ decay is measured to be Br(Bc+J/ψ3π+2π)Br(Bc+J/ψπ+)=1.74±0.44±0.24, \frac{Br (B_c^+ \rightarrow J/\psi 3\pi^+2\pi^)}{Br (B_c^+ \rightarrow J/\psi \pi^+)} = 1.74\pm0.44\pm0.24, where the first uncertainty is statistical and the second is systematic.Evidence is presented for the decay Bc+J/ψ3π+2πB_c+\rightarrow J/\psi 3\pi^+2\pi^- using proton-proton collision data, corresponding to an integrated luminosity of 3fb1^{-1}, collected with the LHCb detector. A signal yield of 32±832\pm8 decays is found with a significance of 4.5 standard deviations. The ratio of the branching fraction of the Bc+J/ψ3π+2πB_c^+\rightarrow J/\psi 3\pi^+ 2\pi^- decay to that of the Bc+J/ψπ+B_c^+ \rightarrow J/\psi \pi^+ decay is measured to be Br(Bc+J/ψ3π+2π)Br(Bc+J/ψπ+)=1.74±0.44±0.24, \frac{Br (B_c^+ \rightarrow J/\psi 3\pi^+2\pi^)}{Br (B_c^+ \rightarrow J/\psi \pi^+)} = 1.74\pm0.44\pm0.24, where the first uncertainty is statistical and the second is systematic
    corecore