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

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 $t\overline{t}$, $W+b\overline{b}$ and $W+c\overline{c}$ 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 $W$ bosons are reconstructed in the decays $W\rightarrow\ell\nu$, where $\ell$ 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

Milk production and ingestive behavior of cows grazing on Marandu and Mulato II pastures under rotational stocking

The objective of this study was to evaluate milk production and ingestive behavior of Holstein cows and the structural characteristics of Mulato II, a hybrid Brachiaria grass CIAT 36087 (B. ruziziensis × B. decumbens × B. brizantha), and Marandu (Brachiaria brizantha cv. Marandu) pastures under rotational stocking. The experiment was conducted from December 2011 to April 2012 after 10 months of adaptation to the grazing management objectives (25 cm pre-grazing height and 15-20 cm post-grazing height). An area of 4 ha was divided into 28 paddocks: 14 with Mulato II pasture and 14 with Marandu pasture. The treatments consisted of the two grasses and a completely randomized design of the grazing variables with six repetitions each (paddock of evaluation) was used. For the animal variables, a randomized matched pairs design of 20 Holstein cows forming 10 blocks of two animals with similar production each was used. The forage mass or accumulation rate did not differ between grasses. Mulato II pastures had a higher tiller population density (822 tillers m−2) and crude protein content (143.5 g kg−1) than Marandu pastures (636 tillers m−2 and 130.3 g kg−1 crude protein). Cows kept on Mulato II exhibited shorter nighttime grazing activity (234 and 246 min in summer and autumn, respectively) than animals kept on Marandu (273 and 394 min, respectively). The average milk yield during the experimental period was higher for Mulato II (15.3 kg cow−1 day−1) compared with Marandu (14.3 kg cow−1 day−1). Both grasses have potential to be used in milk production systems for the grazing management objectives evaluate

Observation of Bs0→D‾∗0ϕB_s^0 \to \overline{D}^{*0} \phi and search for B0→D‾0ϕB^0 \to \overline{D}^0 \phi decays

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 Bs0→D‾0K+K−B_s^0 \to \overline{D}^0 K^+ K^-

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

Observation of a new Ξb−\Xi_b^- resonance

International audienceFrom samples of pp collision data collected by the LHCb experiment at s=7, 8 and 13 TeV, corresponding to integrated luminosities of 1.0, 2.0 and 1.5  fb-1, respectively, a peak in both the Λb0K- and Ξb0π- invariant mass spectra is observed. In the quark model, radially and orbitally excited Ξb- resonances with quark content bds are expected. Referring to this peak as Ξb(6227)-, the mass and natural width are measured to be mΞb(6227)-=6226.9±2.0±0.3±0.2  MeV/c2 and ΓΞb(6227)-=18.1±5.4±1.8  MeV/c2, where the first uncertainty is statistical, the second is systematic, and the third, on mΞb(6227)-, is due to the knowledge of the Λb0 baryon mass. Relative production rates of the Ξb(6227)-→Λb0K- and Ξb(6227)-→Ξb0π- decays are also reported

Observation of Bs0→Dˉ∗0ϕB_s^0 \to \bar{D}^{*0} \phi and search for B0→Dˉ0ϕB^0 \to \bar{D}^0 \phi decays

The first observation of the $B^0_s → \bar{D}^{*0}ϕ$ 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 $B^0 → \bar{D}^0 π^+ π^−$ and is found to be $\mathcal{B}(B^0_s → \bar{D}^{*0}ϕ)=(3.7±0.5±0.3±0.2) × 10^{−5}$, where the first uncertainty is statistical, the second systematic, and the third from the branching fraction of the $B^0 → \bar{D}^0 π^+ π^−$ decay. The fraction of longitudinal polarization in this decay is measured to be $f_L = (73±15±4)\%$. The most precise determination of the branching fraction for the $B^0_s → \bar{D}^{0}ϕ$ decay is also obtained, $\mathcal{B}(B^0_s → \bar{D}^0 ϕ)=(3.0±0.3±0.2±0.2) × 10^{−5}$. An upper limit,$\mathcal{B}(B^0 → \bar{D}^0 ϕ) < 2.0 (2.3) × 10^{−6}$ 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

Model-Independent Observation of Exotic Contributions to B0→J/ψK+π−B^0\to J/\psi K^+\pi^- Decays

International audienceAn angular analysis of B0→J/ψK+π- decays is performed, using proton-proton collision data corresponding to an integrated luminosity of 3  fb-1 collected with the LHCb detector. The m(K+π-) spectrum is divided into fine bins. In each m(K+π-) bin, the hypothesis that the three-dimensional angular distribution can be described by structures induced only by K* resonances is examined, making minimal assumptions about the K+π- system. The data reject the K*-only hypothesis with a large significance, implying the observation of exotic contributions in a model-independent fashion. Inspection of the m(J/ψπ-) vs m(K+π-) plane suggests structures near m(J/ψπ-)=4200 and 4600 MeV

Study of Υ\Upsilon production in ppPb collisions at sNN=8.16\sqrt{s_{NN}}=8.16 TeV

International audienceThe production of ϒ(nS) mesons (n = 1, 2, 3) in pPb and Pbp collisions at a centre-of-mass energy per nucleon pair $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV is measured by the LHCb experiment, using a data sample corresponding to an integrated luminosity of 31.8 nb$^{−1}$. The ϒ(nS) mesons are reconstructed through their decays into two opposite-sign muons. The measurements comprise the differential production cross-sections of the ϒ(1S) and ϒ(2S) states, their forward-to-backward ratios and nuclear modification factors. The measurements are performed as a function of the transverse momentum p$_{T}$ and rapidity in the nucleon-nucleon centre-of-mass frame y$^{*}$ of the ϒ(nS) states, in the kinematic range p$_{T}$ < 25 GeV/c and 1.5 < y$^{*}$ < 4.0 (−5.0 < y$^{*}$ < −2.5) for pPb (Pbp) collisions. In addition, production cross-sections for ϒ(3S) are measured integrated over phase space and the production ratios between all three ϒ(nS) states are determined. Suppression for bottomonium in proton-lead collisions is observed, which is particularly visible in the ratios. The results are compared to theoretical models