304 research outputs found

    Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

    Get PDF
    The production of tt‾ , W+bb‾ and W+cc‾ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓν , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of ttt\overline{t}, W+bbW+b\overline{b} and W+ccW+c\overline{c} is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 ±\pm 0.02 \mbox{fb}^{-1}. The WW bosons are reconstructed in the decays WνW\rightarrow\ell\nu, where \ell denotes muon or electron, while the bb and cc quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions

    Measurement of the J/ψ pair production cross-section in pp collisions at s=13 \sqrt{s}=13 TeV

    Get PDF
    The production cross-section of J/ψ pairs is measured using a data sample of pp collisions collected by the LHCb experiment at a centre-of-mass energy of s=13 \sqrt{s}=13 TeV, corresponding to an integrated luminosity of 279 ±11 pb1^{−1}. The measurement is performed for J/ψ mesons with a transverse momentum of less than 10 GeV/c in the rapidity range 2.0 < y < 4.5. The production cross-section is measured to be 15.2 ± 1.0 ± 0.9 nb. The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the J/ψ pair are measured and compared to theoretical predictions.The production cross-section of J/ψJ/\psi pairs is measured using a data sample of pppp collisions collected by the LHCb experiment at a centre-of-mass energy of s=13TeV\sqrt{s} = 13 \,{\mathrm{TeV}}, corresponding to an integrated luminosity of 279±11pb1279 \pm 11 \,{\mathrm{pb^{-1}}}. The measurement is performed for J/ψJ/\psi mesons with a transverse momentum of less than 10GeV/c10 \,{\mathrm{GeV}}/c in the rapidity range 2.0<y<4.52.0<y<4.5. The production cross-section is measured to be 15.2±1.0±0.9nb15.2 \pm 1.0 \pm 0.9 \,{\mathrm{nb}}. The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the J/ψJ/\psi pair are measured and compared to theoretical predictions

    Measurement of the B0s→μ+μ− Branching Fraction and Effective Lifetime and Search for B0→μ+μ− Decays

    Get PDF
    A search for the rare decays Bs0→μ+μ- and B0→μ+μ- is performed at the LHCb experiment using data collected in pp collisions corresponding to a total integrated luminosity of 4.4  fb-1. An excess of Bs0→μ+μ- decays is observed with a significance of 7.8 standard deviations, representing the first observation of this decay in a single experiment. The branching fraction is measured to be B(Bs0→μ+μ-)=(3.0±0.6-0.2+0.3)×10-9, where the first uncertainty is statistical and the second systematic. The first measurement of the Bs0→μ+μ- effective lifetime, τ(Bs0→μ+μ-)=2.04±0.44±0.05  ps, is reported. No significant excess of B0→μ+μ- decays is found, and a 95% confidence level upper limit, B(B0→μ+μ-)<3.4×10-10, is determined. All results are in agreement with the standard model expectations.A search for the rare decays Bs0μ+μB^0_s\to\mu^+\mu^- and B0μ+μB^0\to\mu^+\mu^- is performed at the LHCb experiment using data collected in pppp collisions corresponding to a total integrated luminosity of 4.4 fb1^{-1}. An excess of Bs0μ+μB^0_s\to\mu^+\mu^- decays is observed with a significance of 7.8 standard deviations, representing the first observation of this decay in a single experiment. The branching fraction is measured to be B(Bs0μ+μ)=(3.0±0.60.2+0.3)×109{\cal B}(B^0_s\to\mu^+\mu^-)=\left(3.0\pm 0.6^{+0.3}_{-0.2}\right)\times 10^{-9}, where the first uncertainty is statistical and the second systematic. The first measurement of the Bs0μ+μB^0_s\to\mu^+\mu^- effective lifetime, τ(Bs0μ+μ)=2.04±0.44±0.05\tau(B^0_s\to\mu^+\mu^-)=2.04\pm 0.44\pm 0.05 ps, is reported. No significant excess of B0μ+μB^0\to\mu^+\mu^- decays is found and a 95 % confidence level upper limit, B(B0μ+μ)<3.4×1010{\cal B}(B^0\to\mu^+\mu^-)<3.4\times 10^{-10}, is determined. All results are in agreement with the Standard Model expectations

    Measurements of prompt charm production cross-sections in pp collisions at s=5 \sqrt{s}=5 TeV

    Get PDF
    Production cross-sections of prompt charm mesons are measured using data from pppp collisions at the LHC at a centre-of-mass energy of 55\,TeV. The data sample corresponds to an integrated luminosity of 8.60±0.338.60\pm0.33\,pb1^{-1} collected by the LHCb experiment. The production cross-sections of D0D^0, D+D^+, Ds+D_s^+, and D+D^{*+} mesons are measured in bins of charm meson transverse momentum, pTp_{\text{T}}, and rapidity, yy. They cover the rapidity range 2.0<y<4.52.0 < y < 4.5 and transverse momentum ranges 0<pT<10GeV/c0 < p_{\text{T}} < 10\, \text{GeV}/c for D0D^0 and D+D^+ and 1<pT<10GeV/c1 < p_{\text{T}} < 10\, \text{GeV}/c for Ds+D_s^+ and D+D^{*+} mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of 1<pT<8GeV/c1 < p_{\text{T}} < 8\, \text{GeV}/c are determined to be \begin{equation*} \sigma(pp\rightarrow D^0 X) = 1190 \pm 3 \pm 64\,\mu\text{b} \end{equation*} \begin{equation*} \sigma(pp\rightarrow D^+ X) = 456 \pm 3 \pm 34\,\mu\text{b} \end{equation*} \begin{equation*} \sigma(pp\rightarrow D_s^+ X) = 195 \pm 4 \pm 19\,\mu\text{b} \end{equation*} \begin{equation*} \sigma(pp\rightarrow D^{*+} X)= 467 \pm 6 \pm 40\,\mu\text{b} \end{equation*} where the uncertainties are statistical and systematic, respectively.Production cross-sections of prompt charm mesons are measured using data from pp collisions at the LHC at a centre-of-mass energy of 5 TeV. The data sample corresponds to an integrated luminosity of 8.60 ± 0.33 pb1^{−1} collected by the LHCb experiment. The production cross-sections of D0^{0}, D+^{+}, Ds+_{s}^{+} , and D+^{∗+} mesons are measured in bins of charm meson transverse momentum, pT_{T}, and rapidity, y. They cover the rapidity range 2.0 < y < 4.5 and transverse momentum ranges 0 < pT_{T} < 10 GeV/c for D0^{0} and D+^{+} and 1 < pT_{T} < 10 GeV/c for Ds+_{s}^{+} and D+^{∗+} mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of 1 < pT_{T} < 8 GeV/c are determined to be σ(ppD0X)=1004±3±54μb,σ(ppD+X)=402±2±30μb,σ(ppDs+X)=170±4±16μb,σ(ppD+X)=421±5±36μb, \begin{array}{l}\sigma \left( pp\to {D}^0X\right)=1004\pm 3\pm 54\mu \mathrm{b},\\ {}\sigma \left( pp\to {D}^{+}X\right)=402\pm 2\pm 30\mu \mathrm{b},\\ {}\sigma \left( pp\to {D}_s^{+}X\right)=170\pm 4\pm 16\mu \mathrm{b},\\ {}\sigma \left( pp\to {D}^{\ast +}X\right)=421\pm 5\pm 36\mu \mathrm{b},\end{array} where the uncertainties are statistical and systematic, respectively.Production cross-sections of prompt charm mesons are measured using data from pppp collisions at the LHC at a centre-of-mass energy of 55\,TeV. The data sample corresponds to an integrated luminosity of 8.60±0.338.60\pm0.33\,pb1^{-1} collected by the LHCb experiment. The production cross-sections of D0D^0, D+D^+, Ds+D_s^+, and D+D^{*+} mesons are measured in bins of charm meson transverse momentum, pTp_{\text{T}}, and rapidity, yy. They cover the rapidity range 2.0<y<4.52.0<y<4.5 and transverse momentum ranges 0<pT<10GeV/c0 < p_{\text{T}} < 10\, \text{GeV}/c for D0D^0 and D+D^+ and 1<pT<10GeV/c1 < p_{\text{T}} < 10\, \text{GeV}/c for Ds+D_s^+ and D+D^{*+} mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of 1<pT<8GeV/c1 < p_{\text{T}} < 8\, \text{GeV}/c are determined to be \sigma(pp\rightarrow D^0 X) = 1004 \pm 3 \pm 54\,\mu\text{b} \sigma(pp\rightarrow D^+ X) = 402 \pm 2 \pm 30\,\mu\text{b} \sigma(pp\rightarrow D_s^+ X) = 170 \pm 4 \pm 16\,\mu\text{b} \sigma(pp\rightarrow D^{*+} X)= 421 \pm 5 \pm 36\,\mu\text{b} where the uncertainties are statistical and systematic, respectively

    Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

    Get PDF
    A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

    stairs and fire

    Get PDF

    Quality Assurance of the VELO Modules and Analysis of the BdKμ+μB_{d}\to K^{*}\mu^{+}\mu^{-} Rare Decay on LHCb.

    No full text
    The LHCb experiment is a high energy physics detector at the Large Hadron Collider. The experiment has been designed and built to search for new physics in the b hadron sector. This thesis discusses a contribution to the detector construction and preparatory studies for a rare decay analysis. Quality assurance of the silicon modules of LHCb vertex detector One of the critical components of the LHCb experiment is the silicon vertex locator (VELO), which is used to measure the decay distance of the b-hadrons and is a principal component of the tracking of the experiment. This thesis describes the quality assurance tests of the VELO silicon modules. A facility was designed to operate the VELO modules in vacuum and thermally stress the modules. To verify the suitability of the modules for the experiment a range of studies were performed including measurements of the silicon leakage current and the identification of bad channels through a noise analysis. A full set of 42 modules (and spares) suitable for use in the experiment were successfully tested. Analysis of the BdKμ+μB_{d}\to K^{*}\mu^{+}\mu^{-}decay The BdKμ+μB_{d}\to K^{*}\mu^{+}\mu^{-} decay is a flavour changing neutral current process which occurs only via loop diagrams. This is a rare process with a measured branching ratio of 1.10^+0.29}_{-0.26} x 10^{-6}. The BdKμ+μB_{d}\to K^{*}\mu^{+}\mu^{-} rare decay is sensitive to new physics (NP) effects. Through the measurement of the so-called forward backward asymmetry distribution a clear signature of NP can be found in this channel. The estimated number of signal events expected per year in LHCb (2fb12fb^{-1}) was estimated to be 7.0±0.1x1037.0\pm0.1x10^{3}. The sensitivity to the zero point of the forward backward asymmetry was calculated as 0.4GeV2/c40.4 GeV^{2}/c^{4}, assuming the estimated annual yield. Degradation of the sensitivity due to background events was estimated to be \tilde 10 - 15%. Potential systematic effects due to acceptance and background mismeasurement are also presented. The results on the forward backward asymmetry were obtained using a non-parametric unbinned method

    Search for narrow resonances using the dijet mass spectrum in pp collisions at s√=8  TeV

    Get PDF
    Results are presented of a search for the production of new particles decaying to pairs of partons (quarks, antiquarks, or gluons), in the dijet mass spectrum in proton-proton collisions at s√=8  TeV. The data sample corresponds to an integrated luminosity of 4.0  fb−1, collected with the CMS detector at the LHC in 2012. No significant evidence for narrow resonance production is observed. Upper limits are set at the 95% confidence level on the production cross section of hypothetical new particles decaying to quark-quark, quark-gluon, or gluon-gluon final states. These limits are then translated into lower limits on the masses of new resonances in specific scenarios of physics beyond the standard model. The limits reach up to 4.8 TeV, depending on the model, and extend previous exclusions from similar searches performed at lower collision energies. For the first time mass limits are set for the Randall–Sundrum graviton model in the dijet channel

    Observation of Bs0D0ϕB_s^0 \to \overline{D}^{*0} \phi and search for B0D0ϕB^0 \to \overline{D}^0 \phi decays

    No full text
    International audienceThe first observation of the Bs0→D¯*0ϕ decay is reported, with a significance of more than seven standard deviations, from an analysis of pp collision data corresponding to an integrated luminosity of 3  fb-1, collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. The branching fraction is measured relative to that of the topologically similar decay B0→D¯0π+π- and is found to be B(Bs0→D¯*0ϕ)=(3.7±0.5±0.3±0.2)×10-5, where the first uncertainty is statistical, the second systematic, and the third from the branching fraction of the B0→D¯0π+π- decay. The fraction of longitudinal polarization in this decay is measured to be fL=(73±15±4)%. The most precise determination of the branching fraction for the Bs0→D¯0ϕ decay is also obtained, B(Bs0→D¯0ϕ)=(3.0±0.3±0.2±0.2)×10-5. An upper limit, B(B0→D¯0ϕ)<2.0 (2.3)×10-6 at 90% (95%) confidence level is set. A constraint on the ω-ϕ mixing angle δ is set at |δ|<5.2° (5.5°) at 90% (95%) confidence level

    Observation of the decay Bs0D0K+KB_s^0 \to \overline{D}^0 K^+ K^-

    No full text
    International audienceThe first observation of the Bs0→D¯0K+K- decay is reported, together with the most precise branching fraction measurement of the mode B0→D¯0K+K-. The results are obtained from an analysis of pp collision data corresponding to an integrated luminosity of 3.0  fb-1. The data were collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. The branching fraction of the B0→D¯0K+K- decay is measured relative to that of the decay B0→D¯0π+π- to be B(B0→D¯0K+K-)B(B0→D¯0π+π-)=(6.9±0.4±0.3)%, where the first uncertainty is statistical and the second is systematic. The measured branching fraction of the Bs0→D¯0K+K- decay mode relative to that of the corresponding B0 decay is B(Bs0→D¯0K+K-)B(B0→D¯0K+K-)=(93.0±8.9±6.9)%. Using the known branching fraction of B0→D¯0π+π-, the values of B(B0→D¯0K+K-)=(6.1±0.4±0.3±0.3)×10-5 and B(Bs0→D¯0K+K-)=(5.7±0.5±0.4±0.5)×10-5 are obtained, where the third uncertainties arise from the branching fraction of the decay modes B0→D¯0π+π- and B0→D¯0K+K-, respectively
    corecore