599 research outputs found

    Весняні ефемероїди флори Кавказу в природі та культурі Національного ботанічного саду імені М.М. Гришка НАН України

    Get PDF
    Objective – to increase the efficiency of introduction of rare Caucasus flora spring ephemeroids (Cyclamen coum Rehb., Helleborus caucasicus A. Braun, Erytronium caucasicum Woronow, Ornithogalum arcuatum Stev., O. ponticum Zahar.) at M.M. Gryshko National Botanical Garden of NАS of Ukraine. Material and methods. In 2011 and 2012 years expeditions were made the trip to the Caucasus for study of natural populations of these species. Comparison of natural and introduction populations, that evolved over several decades in M.M. Gryshko National Botanical Garden of NАS of Ukraine is carried out. Results. All studied species grow well, blossom and bear fruit, formed a stable population of introduction. Only C. coum require artificial support. Conclusion. The study of natural populations allows not only to compare growth conditions and the state of introduction populations from their natural counterparts, but also make the introduction of more effective.Мета – підвищити ефективність інтродукції рідкісних весняних ефемероїдів флори Кавказу (Cyclamen coum Rehb., Helleborus caucasicus A. Braun, Erytronium caucasicum Woronow, Ornithogalum arcuatum Stev., O. ponticum Zahar.) у Національному ботанічному саду імені М.М. Гришка НАН України. Матеріал та методи. У 2011 та 2012 рр. здійснено експедиційні поїздки на Кавказ для вивчення стану природних популяцій зазначених видів. Проведено порівняння стану природних та інтродукційних популяцій, які сформувалися протягом декількох десятиліть у Національному ботанічному саду імені М.М. Гришка НАН України. Результати. Всі вивчені види добре ростуть, цвітуть та плодоносять, утворили стійкі інтродукційні популяції. Лише C. coum потребує штучної підтримки. Висновок. Вивчення природних популяцій дає змогу не лише порівняти умови зростання та стан інтродукційних популяцій з їх природними аналогами, а й зробити інтродукцію більш ефективною

    Asymptotic W-symmetries in three-dimensional higher-spin gauge theories

    Full text link
    We discuss how to systematically compute the asymptotic symmetry algebras of generic three-dimensional bosonic higher-spin gauge theories in backgrounds that are asymptotically AdS. We apply these techniques to a one-parameter family of higher-spin gauge theories that can be considered as large N limits of SL(N) x SL(N) Chern-Simons theories, and we provide a closed formula for the structure constants of the resulting infinite-dimensional non-linear W-algebras. Along the way we provide a closed formula for the structure constants of all classical W_N algebras. In both examples the higher-spin generators of the W-algebras are Virasoro primaries. We eventually discuss how to relate our basis to a non-primary quadratic basis that was previously discussed in literature.Comment: 61 page

    Measurement of D s <sup>±</sup> production asymmetry in pp collisions at √s=7 and 8 TeV

    Get PDF
    The inclusive Ds±D_s^{\pm} production asymmetry is measured in pppp collisions collected by the LHCb experiment at centre-of-mass energies of s=7\sqrt{s} =7 and 8 TeV. Promptly produced Ds±D_s^{\pm} mesons are used, which decay as Ds±ϕπ±D_s^{\pm}\to\phi\pi^{\pm}, with ϕK+K\phi\to K^+K^-. The measurement is performed in bins of transverse momentum, pTp_{\rm T}, and rapidity, yy, covering the range 2.5<pT<25.02.5<p_{\rm T}<25.0 GeV/c/c and 2.0<y<4.52.0<y<4.5. No kinematic dependence is observed. Evidence of nonzero Ds±D_s^{\pm} production asymmetry is found with a significance of 3.3 standard deviations.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2018-010.htm

    Observation and branching fraction measurement of the decay Ξb- → Λ0 bπ -

    Get PDF

    Search for CP violation in Λb0→pK− and Λb0→pπ− decays

    Get PDF
    A search for CP violation in Λb0→pK− and Λb0→pπ− decays is presented using a sample of pp collisions collected with the LHCb detector and corresponding to an integrated luminosity of 3.0fb−1. The CP -violating asymmetries are measured to be ACPpK−=−0.020±0.013±0.019 and ACPpπ−=−0.035±0.017±0.020, and their difference ACPpK−−ACPpπ−=0.014±0.022±0.010, where the first uncertainties are statistical and the second systematic. These are the most precise measurements of such asymmetries to date

    Precision measurement of CP\it{CP} violation in the penguin-mediated decay Bs0ϕϕB_s^{0}\rightarrow\phi\phi

    Get PDF
    A flavor-tagged time-dependent angular analysis of the decay Bs0ϕϕB_s^{0}\rightarrow\phi\phi is performed using pppp collision data collected by the LHCb experiment at % at s=13\sqrt{s}=13 TeV, the center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb^{-1}. The CP\it{CP}-violating phase and direct CP\it{CP}-violation parameter are measured to be ϕssˉs=0.042±0.075±0.009\phi_{s\bar{s}s} = -0.042 \pm 0.075 \pm 0.009 rad and λ=1.004±0.030±0.009|\lambda|=1.004\pm 0.030 \pm 0.009 , respectively, assuming the same values for all polarization states of the ϕϕ\phi\phi system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using pppp collisions at center-of-mass energies of 7 and 8 TeV, yielding ϕssˉs=0.074±0.069\phi_{s\bar{s}s} = -0.074 \pm 0.069 rad and lambda=1.009±0.030|lambda|=1.009 \pm 0.030. This is the most precise study of time-dependent CP\it{CP} violation in a penguin-dominated BB meson decay. The results are consistent with CP\it{CP} symmetry and with the Standard Model predictions.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-001.html (LHCb public pages

    Centrality and transverse momentum dependence of D-0-meson production at mid-rapidity in Au plus Au collisions ats root S-NN=200 GeV

    Get PDF

    Measurement of the Λb0Λ(1520)μ+μ\Lambda_{b}^{0}\to \Lambda(1520) \mu^{+}\mu^{-} differential branching fraction

    Get PDF
    The branching fraction of the rare decay Λb0Λ(1520)μ+μ\Lambda_{b}^{0}\to \Lambda(1520) \mu^{+}\mu^{-} is measured for the first time, in the squared dimuon mass intervals, q2q^2, excluding the J/ψJ/\psi and ψ(2S)\psi(2S) regions. The data sample analyzed was collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of $9\ \mathrm{fb}^{-1}.Theresultinthehighest. The result in the highest q^{2}interval, interval, q^{2} >15.0\ \mathrm{GeV}^2/c^4$, where theoretical predictions have the smallest model dependence, agrees with the predictions.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-050.html (LHCb public pages

    Observation of Two New Excited Ξb0 States Decaying to Λb0 K-π+

    Get PDF
    Two narrow resonant states are observed in the Λb0K-π+ mass spectrum using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 6 fb-1. The minimal quark content of the Λb0K-π+ system indicates that these are excited Ξb0 baryons. The masses of the Ξb(6327)0 and Ξb(6333)0 states are m[Ξb(6327)0]=6327.28-0.21+0.23±0.12±0.24 and m[Ξb(6333)0]=6332.69-0.18+0.17±0.03±0.22 MeV, respectively, with a mass splitting of Δm=5.41-0.27+0.26±0.12 MeV, where the uncertainties are statistical, systematic, and due to the Λb0 mass measurement. The measured natural widths of these states are consistent with zero, with upper limits of Γ[Ξb(6327)0]&lt;2.20(2.56) and Γ[Ξb(6333)0]&lt;1.60(1.92) MeV at a 90% (95%) credibility level. The significance of the two-peak hypothesis is larger than nine (five) Gaussian standard deviations compared to the no-peak (one-peak) hypothesis. The masses, widths, and resonant structure of the new states are in good agreement with the expectations for a doublet of 1D Ξb0 resonances

    Observation of the decay Λ <sub>b</sub> <sup>0</sup>  → ψ(2S)pπ<sup>−</sup>

    Get PDF
    International audienceThe Cabibbo-suppressed decay Λb0_{b}^{0}  → ψ(2S)pπ^{−} is observed for the first time using a data sample collected by the LHCb experiment in proton-proton collisions corresponding to 1.0, 2.0 and 1.9 fb1^{−1} of integrated luminosity at centre-of-mass energies of 7, 8 and 13 TeV, respectively. The ψ(2S) mesons are reconstructed in the μ+^{+}μ^{−} final state. The branching fraction with respect to that of the Λb0_{b}^{0}  → ψ(2S)pK^{−} decay mode is measured to b
    corecore