2,910 research outputs found

    Avaliação de co-infecção de Anticarsia gemmatalis MNPV e Chrysodeixis includens NPV em cultura de células de inseto.

    Get PDF
    Os baculovĂ­rus Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) e Chrysodeixis includens nucleopolyhedrovirus (ChinNPV) que infectam duas importantes pragas da soja, Anticarsia gemmatalis e Chrysodeixis includens, respectivamente, foram testados a respeito da infectividade a diferentes linhagens celulares. As linhagens celulares, IPLBSF-21AE, Sf9 e BTI-Tn-5B1-4, foram previamente definidas como produtivas para infecção de AgMNPV. Neste trabalho a susceptibilidade destas linhagens Ă  infecção simples por ChinNPV e infecção mista de ChinNPV e AgMNPV foram testadas. As cĂ©lulas foram semeadas a uma densidade de 1X106 por placa de 60mm2. Os vĂ­rus foram obtidos a partir de hemolinfa de larvas infectadas, aos 4 dias pĂłs-infecção (d.p.i.), e adsorvidos a cĂ©lulas durante 1 hora (P0). CĂ©lulas infectadas foram mantidas em meio TNMFH completo a 27°C. As cĂ©lulas foram inicialmente monitoradas por microscĂłpio Ăłtico durante cinco dias para realizar as anĂĄlises morfolĂłgicas. Posteriormente, os sobrenadantes foram coletados para novas infecçÔes (P1) usando o mesmo procedimento. Aos 5 d.p.i., os sobrenadantes foram coletados para a segunda passagem (P2). A ultraestrutura dos corpos de oclusĂŁo foi analisada por Microscopia EletrĂŽnica de TransmissĂŁo para a passagem P0. A quantidade de DNA obtida dos Budded Virus (BVs) das trĂȘs passagens foi monitorada por PCR em tempo real (qPCR) usando sistema Sybr green com primers desenhados para gp64 de AgMNPV e photolyase de ChinNPV. Bioensaios foram realizados com larvas de A. gemmatalis e C. includens para comprovação de co-oclusĂŁo na dose estimada de 1 poliedro/larva. Os resultados demonstraram sucesso na co-infecção nestas cĂ©lulas, mas a quantidade de ChinNPV tende a diminuir nas passagens seriais, enquanto a quantidade de AgMNPV tende a aumentar na primeira passagem e estabilizar na segunda passagem. Os resultados de bioensaios comprovaram a presença de poliedros co-ocluidos com ambos os vĂ­rus.bitstream/item/178615/1/boletim333-anticarcia.pd

    Observation of two new Ξb−\Xi_b^- baryon resonances

    Get PDF
    Two structures are observed close to the kinematic threshold in the Ξb0π−\Xi_b^0 \pi^- mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb−1^{-1} recorded by the LHCb experiment. In the quark model, two baryonic resonances with quark content bdsbds are expected in this mass region: the spin-parity JP=12+J^P = \frac{1}{2}^+ and JP=32+J^P=\frac{3}{2}^+ states, denoted Ξbâ€Č−\Xi_b^{\prime -} and Ξb∗−\Xi_b^{*-}. Interpreting the structures as these resonances, we measure the mass differences and the width of the heavier state to be m(Ξbâ€Č−)−m(Ξb0)−m(π−)=3.653±0.018±0.006m(\Xi_b^{\prime -}) - m(\Xi_b^0) - m(\pi^{-}) = 3.653 \pm 0.018 \pm 0.006 MeV/c2/c^2, m(Ξb∗−)−m(Ξb0)−m(π−)=23.96±0.12±0.06m(\Xi_b^{*-}) - m(\Xi_b^0) - m(\pi^{-}) = 23.96 \pm 0.12 \pm 0.06 MeV/c2/c^2, Γ(Ξb∗−)=1.65±0.31±0.10\Gamma(\Xi_b^{*-}) = 1.65 \pm 0.31 \pm 0.10 MeV, where the first and second uncertainties are statistical and systematic, respectively. The width of the lighter state is consistent with zero, and we place an upper limit of Γ(Ξbâ€Č−)<0.08\Gamma(\Xi_b^{\prime -}) < 0.08 MeV at 95% confidence level. Relative production rates of these states are also reported.Comment: 17 pages, 2 figure

    Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays

    Get PDF
    Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201

    Measurement of the mass and lifetime of the Ωb−\Omega_b^- baryon

    Get PDF
    A proton-proton collision data sample, corresponding to an integrated luminosity of 3 fb−1^{-1} collected by LHCb at s=7\sqrt{s}=7 and 8 TeV, is used to reconstruct 63±963\pm9 Ωb−→Ωc0π−\Omega_b^-\to\Omega_c^0\pi^-, Ωc0→pK−K−π+\Omega_c^0\to pK^-K^-\pi^+ decays. Using the Ξb−→Ξc0π−\Xi_b^-\to\Xi_c^0\pi^-, Ξc0→pK−K−π+\Xi_c^0\to pK^-K^-\pi^+ decay mode for calibration, the lifetime ratio and absolute lifetime of the Ωb−\Omega_b^- baryon are measured to be \begin{align*} \frac{\tau_{\Omega_b^-}}{\tau_{\Xi_b^-}} &= 1.11\pm0.16\pm0.03, \\ \tau_{\Omega_b^-} &= 1.78\pm0.26\pm0.05\pm0.06~{\rm ps}, \end{align*} where the uncertainties are statistical, systematic and from the calibration mode (for τΩb−\tau_{\Omega_b^-} only). A measurement is also made of the mass difference, mΩb−−mΞb−m_{\Omega_b^-}-m_{\Xi_b^-}, and the corresponding Ωb−\Omega_b^- mass, which yields \begin{align*} m_{\Omega_b^-}-m_{\Xi_b^-} &= 247.4\pm3.2\pm0.5~{\rm MeV}/c^2, \\ m_{\Omega_b^-} &= 6045.1\pm3.2\pm 0.5\pm0.6~{\rm MeV}/c^2. \end{align*} These results are consistent with previous measurements.Comment: 11 pages, 5 figures, All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-008.htm

    Study of B−→DK−π+π−B^{-}\to DK^-\pi^+\pi^- and B−→Dπ−π+π−B^-\to D\pi^-\pi^+\pi^- decays and determination of the CKM angle Îł\gamma

    Get PDF
    We report a study of the suppressed B−→DK−π+π−B^-\to DK^-\pi^+\pi^- and favored B−→Dπ−π+π−B^-\to D\pi^-\pi^+\pi^- decays, where the neutral DD meson is detected through its decays to the K∓π±K^{\mp}\pi^{\pm} and CP-even K+K−K^+K^- and π+π−\pi^+\pi^- final states. The measurement is carried out using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of 3.0~fb−1^{-1}. We observe the first significant signals in the CP-even final states of the DD meson for both the suppressed B−→DK−π+π−B^-\to DK^-\pi^+\pi^- and favored B−→Dπ−π+π−B^-\to D\pi^-\pi^+\pi^- modes, as well as in the doubly Cabibbo-suppressed D→K+π−D\to K^+\pi^- final state of the B−→Dπ−π+π−B^-\to D\pi^-\pi^+\pi^- decay. Evidence for the ADS suppressed decay B−→DK−π+π−B^{-}\to DK^-\pi^+\pi^-, with D→K+π−D\to K^+\pi^-, is also presented. From the observed yields in the B−→DK−π+π−B^-\to DK^-\pi^+\pi^-, B−→Dπ−π+π−B^-\to D\pi^-\pi^+\pi^- and their charge conjugate decay modes, we measure the value of the weak phase to be Îł=(74−19+20)o\gamma=(74^{+20}_{-19})^{\rm o}. This is one of the most precise single-measurement determinations of Îł\gamma to date.Comment: 22 pages, 9 figures; All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-020.htm

    Evidence for the strangeness-changing weak decay Ξb−→Λb0π−\Xi_b^-\to\Lambda_b^0\pi^-

    Get PDF
    Using a pppp collision data sample corresponding to an integrated luminosity of 3.0~fb−1^{-1}, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay Ξb−→Λb0π−\Xi_b^-\to\Lambda_b^0\pi^-. No bb hadron decay of this type has been seen before. A signal for this decay, corresponding to a significance of 3.2 standard deviations, is reported. The relative rate is measured to be fΞb−fΛb0B(Ξb−→Λb0π−)=(5.7±1.8−0.9+0.8)×10−4{{f_{\Xi_b^-}}\over{f_{\Lambda_b^0}}}{\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) = (5.7\pm1.8^{+0.8}_{-0.9})\times10^{-4}, where fΞb−f_{\Xi_b^-} and fΛb0f_{\Lambda_b^0} are the b→Ξb−b\to\Xi_b^- and b→Λb0b\to\Lambda_b^0 fragmentation fractions, and B(Ξb−→Λb0π−){\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) is the branching fraction. Assuming fΞb−/fΛb0f_{\Xi_b^-}/f_{\Lambda_b^0} is bounded between 0.1 and 0.3, the branching fraction B(Ξb−→Λb0π−){\cal{B}}(\Xi_b^-\to\Lambda_b^0\pi^-) would lie in the range from (0.57±0.21)%(0.57\pm0.21)\% to (0.19±0.07)%(0.19\pm0.07)\%.Comment: 7 pages, 2 figures, All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-047.htm

    Study of the production of Λb0\Lambda_b^0 and B‟0\overline{B}^0 hadrons in pppp collisions and first measurement of the Λb0→J/ψpK−\Lambda_b^0\rightarrow J/\psi pK^- branching fraction

    Get PDF
    The product of the Λb0\Lambda_b^0 (B‟0\overline{B}^0) differential production cross-section and the branching fraction of the decay Λb0→J/ψpK−\Lambda_b^0\rightarrow J/\psi pK^- (B‟0→J/ψK‟∗(892)0\overline{B}^0\rightarrow J/\psi\overline{K}^*(892)^0) is measured as a function of the beauty hadron transverse momentum, pTp_{\rm T}, and rapidity, yy. The kinematic region of the measurements is pT<20 GeV/cp_{\rm T}<20~{\rm GeV}/c and 2.0<y<4.52.0<y<4.5. The measurements use a data sample corresponding to an integrated luminosity of 3 fb−13~{\rm fb}^{-1} collected by the LHCb detector in pppp collisions at centre-of-mass energies s=7 TeV\sqrt{s}=7~{\rm TeV} in 2011 and s=8 TeV\sqrt{s}=8~{\rm TeV} in 2012. Based on previous LHCb results of the fragmentation fraction ratio, fΛB0/fdf_{\Lambda_B^0}/f_d, the branching fraction of the decay Λb0→J/ψpK−\Lambda_b^0\rightarrow J/\psi pK^- is measured to be \begin{equation*} \mathcal{B}(\Lambda_b^0\rightarrow J/\psi pK^-)= (3.17\pm0.04\pm0.07\pm0.34^{+0.45}_{-0.28})\times10^{-4}, \end{equation*} where the first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the branching fraction of the decay B‟0→J/ψK‟∗(892)0\overline{B}^0\rightarrow J/\psi\overline{K}^*(892)^0, and the fourth is due to the knowledge of fΛb0/fdf_{\Lambda_b^0}/f_d. The sum of the asymmetries in the production and decay between Λb0\Lambda_b^0 and Λ‟b0\overline{\Lambda}_b^0 is also measured as a function of pTp_{\rm T} and yy. The previously published branching fraction of Λb0→J/ψpπ−\Lambda_b^0\rightarrow J/\psi p\pi^-, relative to that of Λb0→J/ψpK−\Lambda_b^0\rightarrow J/\psi pK^-, is updated. The branching fractions of Λb0→Pc+(→J/ψp)K−\Lambda_b^0\rightarrow P_c^+(\rightarrow J/\psi p)K^- are determined.Comment: 29 pages, 19figures. All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-032.htm

    BB flavour tagging using charm decays at the LHCb experiment

    Get PDF
    An algorithm is described for tagging the flavour content at production of neutral BB mesons in the LHCb experiment. The algorithm exploits the correlation of the flavour of a BB meson with the charge of a reconstructed secondary charm hadron from the decay of the other bb hadron produced in the proton-proton collision. Charm hadron candidates are identified in a number of fully or partially reconstructed Cabibbo-favoured decay modes. The algorithm is calibrated on the self-tagged decay modes B+→J/ψ K+B^+ \to J/\psi \, K^+ and B0→J/ψ K∗0B^0 \to J/\psi \, K^{*0} using 3.0 fb−13.0\mathrm{\,fb}^{-1} of data collected by the LHCb experiment at pppp centre-of-mass energies of 7 TeV7\mathrm{\,TeV} and 8 TeV8\mathrm{\,TeV}. Its tagging power on these samples of B→J/ψ XB \to J/\psi \, X decays is (0.30±0.01±0.01)%(0.30 \pm 0.01 \pm 0.01) \%.Comment: All figures and tables, along with any supplementary material and additional information, are available at http://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-027.htm

    Observation of an Excited Bc+ State

    Get PDF
    Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+Îł decay following Bc∗(2S31)+→Bc∗(1S31)+π+π-. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date
    • 

    corecore