128 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
The production of tt⟠, W+bb⟠and W+cc⟠is studied in the forward region of protonâproton 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 fbâ1 . The W bosons are reconstructed in the decays WââÎœ , where â 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 , and 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 \mbox{fb}^{-1}. The bosons are reconstructed in the decays , where denotes muon or electron, while the and quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions
Measurement of CP violation parameters and polarisation fractions in decays
The first measurement of asymmetries in the decay and an updated measurement of its branching fraction and polarisation fractions are presented. The results are obtained using data corresponding to an integrated luminosity of of proton-proton collisions recorded with the LHCb detector at centre-of-mass energies of and . Together with constraints from , the results are used to constrain additional contributions due to penguin diagrams in the -violating phase , measured through decays to charmonium.The first measurement of CP asymmetries in the decay and an updated measurement of its branching fraction and polarisation fractions are presented. The results are obtained using data corresponding to an integrated luminosity of 3.0 fb^{â}^{1} of proton-proton collisions recorded with the LHCb detector at centre-of-mass energies of 7 and 8 TeV. Together with constraints from B â J/Ï Ï, the results are used to constrain additional contributions due to penguin diagrams in the CP -violating phase Ï , measured through B decays to charmonium.The first measurement of asymmetries in the decay and an updated measurement of its branching fraction and polarisation fractions are presented. The results are obtained using data corresponding to an integrated luminosity of of proton-proton collisions recorded with the LHCb detector at centre-of-mass energies of and . Together with constraints from , the results are used to constrain additional contributions due to penguin diagrams in the -violating phase , measured through decays to charmonium
Measurement of the J/Ï pair production cross-section in pp collisions at TeV
The production cross-section of J/Ï pairs is measured using a data sample of pp collisions collected by the LHCb experiment at a centre-of-mass energy of TeV, corresponding to an integrated luminosity of 279 ±11 pb. The measurement is performed for J/Ï 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/Ï pair are measured and compared to theoretical predictions.The production cross-section of pairs is measured using a data sample of collisions collected by the LHCb experiment at a centre-of-mass energy of , corresponding to an integrated luminosity of . The measurement is performed for mesons with a transverse momentum of less than in the rapidity range . The production cross-section is measured to be . The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the pair are measured and compared to theoretical predictions
Measurement of forward production in collisions at TeV
A measurement of the cross-section for production in collisions is presented using data corresponding to an integrated luminosity of fb collected by the LHCb experiment at a centre-of-mass energy of TeV. The electrons are required to have more than GeV of transverse momentum and to lie between 2.00 and 4.25 in pseudorapidity. The inclusive production cross-sections, where the decays to , are measured to be \begin{align*} \begin{split} \sigma_{W^{+} \to e^{+}\nu_{e}}&=1124.4\pm 2.1\pm 21.5\pm 11.2\pm 13.0\,\mathrm{pb},\\ \sigma_{W^{-} \to e^{-}\bar{\nu}_{e}}&=\,\,\,809.0\pm 1.9\pm 18.1\pm\,\,\,7.0\pm \phantom{0}9.4\,\mathrm{pb}, \end{split} \end{align*} where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination. Differential cross-sections as a function of the electron pseudorapidity are measured. The cross-section ratio and production charge asymmetry are also reported. Results are compared with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. Finally, in a precise test of lepton universality, the ratio of boson branching fractions is determined to be \begin{align*} \begin{split} \mathcal{B}(W \to e\nu)/\mathcal{B}(W \to \mu\nu)=1.020\pm 0.002\pm 0.019, \end{split} \end{align*} where the first uncertainty is statistical and the second is systematic.A measurement of the cross-section for production in collisions is presented using data corresponding to an integrated luminosity of fb collected by the LHCb experiment at a centre-of-mass energy of TeV. The electrons are required to have more than GeV of transverse momentum and to lie between 2.00 and 4.25 in pseudorapidity. The inclusive production cross-sections, where the decays to , are measured to be \begin{equation*} \sigma_{W^{+} \to e^{+}\nu_{e}}=1124.4\pm 2.1\pm 21.5\pm 11.2\pm 13.0\,\mathrm{pb}, \end{equation*} \begin{equation*} \sigma_{W^{-} \to e^{-}\bar{\nu}_{e}}=\,\,\,809.0\pm 1.9\pm 18.1\pm\,\,\,7.0\pm \phantom{0}9.4\,\mathrm{pb}, \end{equation*} where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination. Differential cross-sections as a function of the electron pseudorapidity are measured. The cross-section ratio and production charge asymmetry are also reported. Results are compared with theoretical predictions at next-to-next-to-leading order in perturbative quantum chromodynamics. Finally, in a precise test of lepton universality, the ratio of boson branching fractions is determined to be \begin{equation*} \mathcal{B}(W \to e\nu)/\mathcal{B}(W \to \mu\nu)=1.020\pm 0.002\pm 0.019, \end{equation*} where the first uncertainty is statistical and the second is systematic.A measurement of the cross-section for W â eÎœ production in pp collisions is presented using data corresponding to an integrated luminosity of 2 fb collected by the LHCb experiment at a centre-of-mass energy of TeV. The electrons are required to have more than 20 GeV of transverse momentum and to lie between 2.00 and 4.25 in pseudorapidity. The inclusive W production cross-sections, where the W decays to eÎœ, are measured to be where the first uncertainties are statistical, the second are systematic, the third are due to the knowledge of the LHC beam energy and the fourth are due to the luminosity determination
Measurement of the B0sâÎŒ+ÎŒâ Branching Fraction and Effective Lifetime and Search for B0âÎŒ+ÎŒâ Decays
A search for the rare decays Bs0âÎŒ+ÎŒ- and B0âÎŒ+ÎŒ- is performed at the LHCb experiment using data collected in pp collisions corresponding to a total integrated luminosity of 4.4ââfb-1. An excess of Bs0âÎŒ+ÎŒ- 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(Bs0âÎŒ+ÎŒ-)=(3.0±0.6-0.2+0.3)Ă10-9, where the first uncertainty is statistical and the second systematic. The first measurement of the Bs0âÎŒ+ÎŒ- effective lifetime, Ï(Bs0âÎŒ+ÎŒ-)=2.04±0.44±0.05ââps, is reported. No significant excess of B0âÎŒ+ÎŒ- decays is found, and a 95% confidence level upper limit, B(B0âÎŒ+ÎŒ-)<3.4Ă10-10, is determined. All results are in agreement with the standard model expectations.A search for the rare decays and is performed at the LHCb experiment using data collected in collisions corresponding to a total integrated luminosity of 4.4 fb. An excess of 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 , where the first uncertainty is statistical and the second systematic. The first measurement of the effective lifetime, ps, is reported. No significant excess of decays is found and a 95 % confidence level upper limit, , is determined. All results are in agreement with the Standard Model expectations
Measurements of prompt charm production cross-sections in pp collisions at TeV
Production cross-sections of prompt charm mesons are measured using data from collisions at the LHC at a centre-of-mass energy of TeV. The data sample corresponds to an integrated luminosity of pb collected by the LHCb experiment. The production cross-sections of , , , and mesons are measured in bins of charm meson transverse momentum, , and rapidity, . They cover the rapidity range and transverse momentum ranges for and and for and mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of 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 pb collected by the LHCb experiment. The production cross-sections of D, D, D , and D mesons are measured in bins of charm meson transverse momentum, p, and rapidity, y. They cover the rapidity range 2.0 < y < 4.5 and transverse momentum ranges 0 < p < 10 GeV/c for D and D and 1 < p < 10 GeV/c for D and D mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of 1 < p < 8 GeV/c are determined to be where the uncertainties are statistical and systematic, respectively.Production cross-sections of prompt charm mesons are measured using data from collisions at the LHC at a centre-of-mass energy of TeV. The data sample corresponds to an integrated luminosity of pb collected by the LHCb experiment. The production cross-sections of , , , and mesons are measured in bins of charm meson transverse momentum, , and rapidity, . They cover the rapidity range and transverse momentum ranges for and and for and mesons. The inclusive cross-sections for the four mesons, including charge-conjugate states, within the range of 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
Measurement of the B0sâÎŒ+ÎŒâ Branching Fraction and Effective Lifetime and Search for B0âÎŒ+ÎŒâ Decays
See paper for full list of authors - 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-2017-001.html - Submitted to Phys. Rev. Lett.International audienceA search for the rare decays B0sâÎŒ+ÎŒâ and B0âÎŒ+ÎŒâ is performed at the LHCb experiment using data collected in pp collisions corresponding to a total integrated luminosity of 4.4 fbâ1. An excess of B0sâÎŒ+ÎŒâ 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(B0sâÎŒ+ÎŒâ)=(3.0±0.6+0.3â0.2)Ă10â9, where the first uncertainty is statistical and the second systematic. The first measurement of the B0sâÎŒ+ÎŒâ effective lifetime, Ï(B0sâÎŒ+ÎŒâ)=2.04±0.44±0.05 ps, is reported. No significant excess of B0âÎŒ+ÎŒâ decays is found and a 95 % confidence level upper limit, B(B0âÎŒ+ÎŒâ)<3.4Ă10â10, is determined. All results are in agreement with the Standard Model expectations
Antimicrobial use and antimicrobial resistance in Enterobacterales and Enterococcus faecium: a time series analysis
Background: Irish and European antimicrobial resistance (AMR) surveillance data have highlighted increasing AMR in Enterobacterales and vancomycin resistance in Enterococcus faecium (VRE). Antimicrobial consumption (AC) in Irish hospital settings is also increasing. Methods: A retrospective time series analysis (TSA) was conducted to evaluate the trends and possible relationship between AC of selected antimicrobials and AMR in Enterobacterales and vancomycin resistance in E. faecium, from January 2017 to December 2020. Results: Increased AC was seen with ceftriaxone (P = 0.0006), piperacillin/tazobactam (P = 0.03) and meropenem (P = 0.054), while ciprofloxacin and gentamicin use trended downwards. AMR rates in Escherichia coli, Klebsiella pneumoniae and other Enterobacterales were largely stable or decreasing, an increase in ertapenem resistance in the latter from 0.58% in 2017 to 5.19% in 2020 (P = 0.003) being the main concern. The proportion of E. faecium that was VRE did not changed significantly (64% in 2017; 53% in 2020, P = 0.1). TSA identified a correlation between piperacillin/tazobactam use and the decreasing rate of ceftriaxone resistance in E. coli. Conclusion: Our data suggest that the hospital antimicrobial stewardship programme is largely containing, but not reducing AMR in key nosocomial pathogens. An increase in AC following the COVID-19 pandemic appears as yet to have had no impact on AMR rates
Proton relay reaction in green fluorescent protein (GFP): Polarization-resolved ultrafast vibrational spectroscopy of isotopically edited GFP
The complex transient vibrational spectra of wild type (wt) GFP have been assigned through polarization anisotropy measurements on isotopically edited proteins. Protein chromophore interactions modify considerably the vibrational structure, compared to the model chromophore in solution. An excited-state vibrational mode yields information on excited-state electronic structure. The proton relay pathway is characterized in more detail, and the protonation of the remote E222 residue is shown to occur in a concerted step. Modifications to protein vibrational modes are shown to occur following electronic excitation, and the potential for these to act as a trigger to the proton relay reaction is discussed
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