169 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

    Observation of the B0 → ρ0ρ0 decay from an amplitude analysis of B0 → (π+π−)(π+π−) decays

    Get PDF
    Proton–proton collision data recorded in 2011 and 2012 by the LHCb experiment, corresponding to an integrated luminosity of 3.0 fb−1 , are analysed to search for the charmless B0→ρ0ρ0 decay. More than 600 B0→(π+π−)(π+π−) signal decays are selected and used to perform an amplitude analysis, under the assumption of no CP violation in the decay, from which the B0→ρ0ρ0 decay is observed for the first time with 7.1 standard deviations significance. The fraction of B0→ρ0ρ0 decays yielding a longitudinally polarised final state is measured to be fL=0.745−0.058+0.048(stat)±0.034(syst) . The B0→ρ0ρ0 branching fraction, using the B0→ϕK⁎(892)0 decay as reference, is also reported as B(B0→ρ0ρ0)=(0.94±0.17(stat)±0.09(syst)±0.06(BF))×10−6

    Measurement of the (eta c)(1S) production cross-section in proton-proton collisions via the decay (eta c)(1S) -> p(p)over-bar

    Get PDF
    The production of the ηc(1S)\eta_c (1S) state in proton-proton collisions is probed via its decay to the ppˉp \bar{p} final state with the LHCb detector, in the rapidity range 2.06.52.0 6.5 GeV/c. The cross-section for prompt production of ηc(1S)\eta_c (1S) mesons relative to the prompt J/ψJ/\psi cross-section is measured, for the first time, to be σηc(1S)/σJ/ψ=1.74±0.29±0.28±0.18B\sigma_{\eta_c (1S)}/\sigma_{J/\psi} = 1.74 \pm 0.29 \pm 0.28 \pm 0.18 _{B} at a centre-of-mass energy s=7\sqrt{s} = 7 TeV using data corresponding to an integrated luminosity of 0.7 fb1^{-1}, and σηc(1S)/σJ/ψ=1.60±0.29±0.25±0.17B\sigma_{\eta_c (1S)}/\sigma_{J/\psi} = 1.60 \pm 0.29 \pm 0.25 \pm 0.17 _{B} at s=8\sqrt{s} = 8 TeV using 2.0 fb1^{-1}. The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the ηc(1S)\eta_c (1S) and J/ψJ/\psi decays to the ppˉp \bar{p} final state. In addition, the inclusive branching fraction of bb-hadron decays into ηc(1S)\eta_c (1S) mesons is measured, for the first time, to be B(bηcX)=(4.88±0.64±0.25±0.67B)×103B ( b \rightarrow \eta_c X ) = (4.88 \pm 0.64 \pm 0.25 \pm 0.67 _{B}) \times 10^{-3}, where the third uncertainty includes also the uncertainty on the J/ψJ/\psi inclusive branching fraction from bb-hadron decays. The difference between the J/ψJ/\psi and ηc(1S)\eta_c (1S) meson masses is determined to be 114.7±1.5±0.1114.7 \pm 1.5 \pm 0.1 MeV/c2^2.The production of the ηc(1S)\eta _c (1S) state in proton-proton collisions is probed via its decay to the ppp\overline{p} final state with the LHCb detector, in the rapidity range 2.06.5GeV/c2.0 6.5 \mathrm{{\,GeV/}{ c}} . The cross-section for prompt production of ηc(1S)\eta _c (1S) mesons relative to the prompt J/ψ{{ J}}/{\psi } cross-section is measured, for the first time, to be σηc(1S)/σJ/ψ=1.74±0.29±0.28±0.18B\sigma _{\eta _c (1S)}/\sigma _{{{{ J}}/{\psi }}} = 1.74\, \pm \,0.29\, \pm \, 0.28\, \pm \,0.18 _{{\mathcal{B}}} at a centre-of-mass energy s=7 TeV{\sqrt{s}} = 7 {~\mathrm{TeV}} using data corresponding to an integrated luminosity of 0.7 fb1^{-1} , and σηc(1S)/σJ/ψ=1.60±0.29±0.25±0.17B\sigma _{\eta _c (1S)}/\sigma _{{{{ J}}/{\psi }}} = 1.60 \pm 0.29 \pm 0.25 \pm 0.17 _{{\mathcal{B}}} at s=8 TeV{\sqrt{s}} = 8 {~\mathrm{TeV}} using 2.0 fb1^{-1} . The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the ηc(1S)\eta _c (1S) and J/ψ{{ J}}/{\psi } decays to the ppp\overline{p} final state. In addition, the inclusive branching fraction of b{b} -hadron decays into ηc(1S)\eta _c (1S) mesons is measured, for the first time, to be B(bηcX)=(4.88±0.64±0.29±0.67B)×103{\mathcal{B}}( b {\rightarrow } \eta _c X ) = (4.88\, \pm \,0.64\, \pm \,0.29\, \pm \, 0.67 _{{\mathcal{B}}}) \times 10^{-3} , where the third uncertainty includes also the uncertainty on the J/ψ{{ J}}/{\psi } inclusive branching fraction from b{b} -hadron decays. The difference between the J/ψ{{ J}}/{\psi } and ηc(1S)\eta _c (1S) meson masses is determined to be 114.7±1.5±0.1MeV ⁣/c2114.7 \pm 1.5 \pm 0.1 {\mathrm {\,MeV\!/}c^2} .The production of the ηc(1S)\eta_c (1S) state in proton-proton collisions is probed via its decay to the ppˉp \bar{p} final state with the LHCb detector, in the rapidity range 2.06.52.0 6.5 GeV/c. The cross-section for prompt production of ηc(1S)\eta_c (1S) mesons relative to the prompt J/ψJ/\psi cross-section is measured, for the first time, to be σηc(1S)/σJ/ψ=1.74±0.29±0.28±0.18B\sigma_{\eta_c (1S)}/\sigma_{J/\psi} = 1.74 \pm 0.29 \pm 0.28 \pm 0.18 _{B} at a centre-of-mass energy s=7\sqrt{s} = 7 TeV using data corresponding to an integrated luminosity of 0.7 fb1^{-1}, and σηc(1S)/σJ/ψ=1.60±0.29±0.25±0.17B\sigma_{\eta_c (1S)}/\sigma_{J/\psi} = 1.60 \pm 0.29 \pm 0.25 \pm 0.17 _{B} at s=8\sqrt{s} = 8 TeV using 2.0 fb1^{-1}. The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the ηc(1S)\eta_c (1S) and J/ψJ/\psi decays to the ppˉp \bar{p} final state. In addition, the inclusive branching fraction of bb-hadron decays into ηc(1S)\eta_c (1S) mesons is measured, for the first time, to be B(bηcX)=(4.88±0.64±0.29±0.67B)×103B ( b \rightarrow \eta_c X ) = (4.88 \pm 0.64 \pm 0.29 \pm 0.67 _{B}) \times 10^{-3}, where the third uncertainty includes also the uncertainty on the J/ψJ/\psi inclusive branching fraction from bb-hadron decays. The difference between the J/ψJ/\psi and ηc(1S)\eta_c (1S) meson masses is determined to be 114.7±1.5±0.1114.7 \pm 1.5 \pm 0.1 MeV/c2^2

    Angular analysis of the B-0 -> K*(0) e(+) e(-) decay in the low-q(2) region

    Get PDF
    An angular analysis of the B0K0e+eB^0 \rightarrow K^{*0} e^+ e^- decay is performed using a data sample, corresponding to an integrated luminosity of 3.0 {\mbox{fb}^{-1}}, collected by the LHCb experiment in pppp collisions at centre-of-mass energies of 7 and 8 TeV during 2011 and 2012. For the first time several observables are measured in the dielectron mass squared (q2q^2) interval between 0.002 and 1.120GeV2 ⁣/c4{\mathrm{\,Ge\kern -0.1em V^2\!/}c^4}. The angular observables FLF_{\mathrm{L}} and ATReA_{\mathrm{T}}^{\mathrm{Re}} which are related to the K0K^{*0} polarisation and to the lepton forward-backward asymmetry, are measured to be FL=0.16±0.06±0.03F_{\mathrm{L}}= 0.16 \pm 0.06 \pm0.03 and ATRe=0.10±0.18±0.05A_{\mathrm{T}}^{\mathrm{Re}} = 0.10 \pm 0.18 \pm 0.05, where the first uncertainty is statistical and the second systematic. The angular observables AT(2)A_{\mathrm{T}}^{(2)} and ATImA_{\mathrm{T}}^{\mathrm{Im}} which are sensitive to the photon polarisation in this q2q^2 range, are found to be AT(2)=0.23±0.23±0.05A_{\mathrm{T}}^{(2)} = -0.23 \pm 0.23 \pm 0.05 and ATIm=0.14±0.22±0.05A_{\mathrm{T}}^{\mathrm{Im}} =0.14 \pm 0.22 \pm 0.05. The results are consistent with Standard Model predictions.An angular analysis of the B0^{0} → K^{*}^{0} e+^{+} e^{−} decay is performed using a data sample, corresponding to an integrated luminosity of 3.0 fb1^{−1}, collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV during 2011 and 2012. For the first time several observables are measured in the dielectron mass squared (q2^{2}) interval between 0.002 and 1.120 GeV2^{2} /c4^{4}. The angular observables FL_{L} and ATRe_{T}^{Re} which are related to the K^{*}^{0} polarisation and to the lepton forward-backward asymmetry, are measured to be FL_{L} = 0.16 ± 0.06 ± 0.03 and ATRe_{T}^{Re}  = 0.10 ± 0.18 ± 0.05, where the first uncertainty is statistical and the second systematic. The angular observables AT(2)_{T}^{(2)} and ATIm_{T}^{Im} which are sensitive to the photon polarisation in this q2^{2} range, are found to be AT(2)_{T}^{(2)}  = − 0.23 ± 0.23 ± 0.05 and ATIm_{T}^{Im}  = 0.14 ± 0.22 ± 0.05. The results are consistent with Standard Model predictions.An angular analysis of the B0K0e+eB^0 \rightarrow K^{*0} e^+ e^- decay is performed using a data sample, corresponding to an integrated luminosity of 3.0 {\mbox{fb}^{-1}}, collected by the LHCb experiment in pppp collisions at centre-of-mass energies of 7 and 8 TeV during 2011 and 2012. For the first time several observables are measured in the dielectron mass squared (q2q^2) interval between 0.002 and 1.120GeV2 ⁣/c4{\mathrm{\,Ge\kern -0.1em V^2\!/}c^4}. The angular observables FLF_{\mathrm{L}} and ATReA_{\mathrm{T}}^{\mathrm{Re}} which are related to the K0K^{*0} polarisation and to the lepton forward-backward asymmetry, are measured to be FL=0.16±0.06±0.03F_{\mathrm{L}}= 0.16 \pm 0.06 \pm0.03 and ATRe=0.10±0.18±0.05A_{\mathrm{T}}^{\mathrm{Re}} = 0.10 \pm 0.18 \pm 0.05, where the first uncertainty is statistical and the second systematic. The angular observables AT(2)A_{\mathrm{T}}^{(2)} and ATImA_{\mathrm{T}}^{\mathrm{Im}} which are sensitive to the photon polarisation in this q2q^2 range, are found to be AT(2)=0.23±0.23±0.05A_{\mathrm{T}}^{(2)} = -0.23 \pm 0.23 \pm 0.05 and ATIm=0.14±0.22±0.05A_{\mathrm{T}}^{\mathrm{Im}} =0.14 \pm 0.22 \pm 0.05. The results are consistent with Standard Model predictions

    Measurement of the Z plus b-jet cross-section in pp collisions at root s=7 TeV in the forward region

    Get PDF
    The associated production of a Z boson or an off-shell photon γ\gamma^* with a bottom quark in the forward region is studied using proton-proton collisions at a centre-of-mass energy of 7TeV7{\mathrm{\,Te\kern -0.1em V}}. The Z bosons are reconstructed in the Z/γμ+μ{\text{Z}/\gamma^*}\rightarrow{\mu^{+}\mu^{-}} final state from muons with a transverse momentum larger than 20GeV20{\mathrm{\,Ge\kern -0.1em V}}, while two transverse momentum thresholds are considered for jets (10GeV10{\mathrm{\,Ge\kern -0.1em V}} and 20GeV20{\mathrm{\,Ge\kern -0.1em V}}). Both muons and jets are reconstructed in the pseudorapidity range 2.010GeV2.0 10{\mathrm{\,Ge\kern -0.1em V}}, and \sigma(\text{\text{Z}/\gamma^*(\mu^{+}\mu^{-})+b-jet}) = 167 \pm 47 (\text{stat}) \pm 29 (\text{syst}) \pm 6 (\text{lumi}) {\,{fb}} for {p_{\rm T}}(jet)>20GeV>20{\mathrm{\,Ge\kern -0.1em V}}

    Study of the rare B-s(0) and B-0 decays into the pi(+) pi(-) mu(+) mu(-) final state

    Get PDF
    A search for the rare decays Bs0π+πμ+μB_s^0 \to \pi^+\pi^-\mu^+\mu^- and B0π+πμ+μB^0 \to \pi^+\pi^-\mu^+\mu^- is performed in a data set corresponding to an integrated luminosity of 3.0 fb1^{-1} collected by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. Decay candidates with pion pairs that have invariant mass in the range 0.5-1.3 GeV/c2c^2 and with muon pairs that do not originate from a resonance are considered. The first observation of the decay Bs0π+πμ+μB_s^0 \to \pi^+\pi^-\mu^+\mu^- and the first evidence of the decay B0π+πμ+μB^0 \to \pi^+\pi^-\mu^+\mu^- are obtained and the branching fractions are measured to be B(Bs0π+πμ+μ)=(8.6±1.5(stat)±0.7(syst)±0.7(norm))×108\mathcal{B}(B_s^0 \to \pi^+\pi^-\mu^+\mu^-)=(8.6\pm 1.5\,({\rm stat}) \pm 0.7\,({\rm syst})\pm 0.7\,({\rm norm}))\times 10^{-8} and B(B0π+πμ+μ)=(2.11±0.51(stat)±0.15(syst)±0.16(norm))×108\mathcal{B}(B^0 \to \pi^+\pi^-\mu^+\mu^-)=(2.11\pm 0.51\,({\rm stat}) \pm 0.15\,({\rm syst})\pm 0.16\,({\rm norm}) )\times 10^{-8}, where the third uncertainty is due to the branching fraction of the decay B0J/ψ(μ+μ)K(890)0(K+π)B^0\to J/\psi(\to \mu^+\mu^-)K^*(890)^0(\to K^+\pi^-), used as a normalisation.A search for the rare decays Bs0→π+π−μ+μ− and B0→π+π−μ+μ− is performed in a data set corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb detector in proton–proton collisions at centre-of-mass energies of 7 and 8 TeV . Decay candidates with pion pairs that have invariant mass in the range 0.5–1.3 GeV/c2 and with muon pairs that do not originate from a resonance are considered. The first observation of the decay Bs0→π+π−μ+μ− and the first evidence of the decay B0→π+π−μ+μ− are obtained and the branching fractions, restricted to the dipion-mass range considered, are measured to be B(Bs0→π+π−μ+μ−)=(8.6±1.5 (stat)±0.7 (syst)±0.7(norm))×10−8 and B(B0→π+π−μ+μ−)=(2.11±0.51(stat)±0.15(syst)±0.16(norm))×10−8 , where the third uncertainty is due to the branching fraction of the decay B0→J/ψ(→μ+μ−)K⁎(892)0(→K+π−) , used as a normalisation.A search for the rare decays Bs0→π+π−μ+μ− and B0→π+π−μ+μ− is performed in a data set corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb detector in proton–proton collisions at centre-of-mass energies of 7 and 8 TeV . Decay candidates with pion pairs that have invariant mass in the range 0.5–1.3 GeV/c2 and with muon pairs that do not originate from a resonance are considered. The first observation of the decay Bs0→π+π−μ+μ− and the first evidence of the decay B0→π+π−μ+μ− are obtained and the branching fractions, restricted to the dipion-mass range considered, are measured to be B(Bs0→π+π−μ+μ−)=(8.6±1.5 (stat)±0.7 (syst)±0.7(norm))×10−8 and B(B0→π+π−μ+μ−)=(2.11±0.51(stat)±0.15(syst)±0.16(norm))×10−8 , where the third uncertainty is due to the branching fraction of the decay B0→J/ψ(→μ+μ−)K⁎(892)0(→K+π−) , used as a normalisation.A search for the rare decays Bs0π+πμ+μB_s^0 \to \pi^+\pi^-\mu^+\mu^- and B0π+πμ+μB^0 \to \pi^+\pi^-\mu^+\mu^- is performed in a data set corresponding to an integrated luminosity of 3.0 fb1^{-1} collected by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. Decay candidates with pion pairs that have invariant mass in the range 0.5-1.3 GeV/c2c^2 and with muon pairs that do not originate from a resonance are considered. The first observation of the decay Bs0π+πμ+μB_s^0 \to \pi^+\pi^-\mu^+\mu^- and the first evidence of the decay B0π+πμ+μB^0 \to \pi^+\pi^-\mu^+\mu^- are obtained and the branching fractions, restricted to the dipion-mass range considered, are measured to be B(Bs0π+πμ+μ)=(8.6±1.5(stat)±0.7(syst)±0.7(norm))×108\mathcal{B}(B_s^0 \to \pi^+\pi^-\mu^+\mu^-)=(8.6\pm 1.5\,({\rm stat}) \pm 0.7\,({\rm syst})\pm 0.7\,({\rm norm}))\times 10^{-8} and B(B0π+πμ+μ)=(2.11±0.51(stat)±0.15(syst)±0.16(norm))×108\mathcal{B}(B^0 \to \pi^+\pi^-\mu^+\mu^-)=(2.11\pm 0.51\,({\rm stat}) \pm 0.15\,({\rm syst})\pm 0.16\,({\rm norm}) )\times 10^{-8}, where the third uncertainty is due to the branching fraction of the decay B0J/ψ(μ+μ)K(890)0(K+π)B^0\to J/\psi(\to \mu^+\mu^-)K^*(890)^0(\to K^+\pi^-), used as a normalisation

    Search for CP violation using T-odd correlations in D-0 -> K+K-pi(+)pi(-) decays

    Get PDF
    A search for CPCP violation using TT-odd correlations is performed using the four-body D0K+Kπ+πD^0 \to K^+K^-\pi^+\pi^- decay, selected from semileptonic BB decays. The data sample corresponds to integrated luminosities of 1.0fb11.0\,\text{fb}^{-1} and 2.0fb12.0\,\text{fb}^{-1} recorded at the centre-of-mass energies of 7 TeV and 8 TeV, respectively. The CPCP-violating asymmetry aCPT-odda_{CP}^{T\text{-odd}} is measured to be (0.18±0.29(stat)±0.04(syst))%(0.18\pm 0.29\text{(stat)}\pm 0.04\text{(syst)})\%. Searches for CPCP violation in different regions of phase space of the four-body decay, and as a function of the D0D^0 decay time, are also presented. No significant deviation from the CPCP conservation hypothesis is found

    Measurement of CP asymmetry in B-s(0) -> D-s(-/+) K--/+ decays

    Get PDF
    We report on measurements of the time-dependent CP violating observables in Bs0DsK±B^0_s\rightarrow D^{\mp}_s K^{\pm} decays using a dataset corresponding to 1.0 fb1^{-1} of pp collisions recorded with the LHCb detector. We find the CP violating observables Cf=0.53±0.25±0.04C_f=0.53\pm0.25\pm0.04, AfΔΓ=0.37±0.42±0.20A^{\Delta\Gamma}_f=0.37\pm0.42\pm0.20, AfˉΔΓ=0.20±0.41±0.20A^{\Delta\Gamma}_{\bar{f}}=0.20\pm0.41\pm0.20, Sf=1.09±0.33±0.08S_f=-1.09\pm0.33\pm0.08, Sfˉ=0.36±0.34±0.08S_{\bar{f}}=-0.36\pm0.34\pm0.08, where the uncertainties are statistical and systematic, respectively. We use these observables to make the first measurement of the CKM angle γ\gamma in Bs0DsK±B^0_s\rightarrow D^{\mp}_s K^{\pm} decays, finding γ\gamma = (11543+28_{-43}^{+28})^\circ modulo 180^\circ at 68% CL, where the error contains both statistical and systematic uncertainties.We report on measurements of the time-dependent CP violating observables in Bs0_{s}^{0}  → Ds_{s}^{∓} K±^{±} decays using a dataset corresponding to 1.0 fb1^{−1} of pp collisions recorded with the LHCb detector. We find the CP violating observables Cf_{f} = 0.53±0.25±0.04, AfΔΓ_{f}^{ΔΓ}  = 0.37 ± 0.42 ± 0.20, AfΔΓ=0.20±0.41±0.20 {A}_{\overline{f}}^{\varDelta \varGamma }=0.20\pm 0.41\pm 0.20 , Sf_{f} = −1.09±0.33±0.08, Sf=0.36±0.34±0.08 {S}_{\overline{f}}=-0.36\pm 0.34\pm 0.08 , where the uncertainties are statistical and systematic, respectively. Using these observables together with a recent measurement of the Bs0_{s}^{0} mixing phase −2βs_{s} leads to the first extraction of the CKM angle γ from Bs0_{s}^{0}  → Ds_{s}^{∓} K±^{±} decays, finding γ = (11543+28_{− 43}^{+ 28} )° modulo 180° at 68% CL, where the error contains both statistical and systematic uncertainties.We report on measurements of the time-dependent CP violating observables in Bs0DsK±B^0_s\rightarrow D^{\mp}_s K^{\pm} decays using a dataset corresponding to 1.0 fb1^{-1} of pp collisions recorded with the LHCb detector. We find the CP violating observables Cf=0.53±0.25±0.04C_f=0.53\pm0.25\pm0.04, AfΔΓ=0.37±0.42±0.20A^{\Delta\Gamma}_f=0.37\pm0.42\pm0.20, AfˉΔΓ=0.20±0.41±0.20A^{\Delta\Gamma}_{\bar{f}}=0.20\pm0.41\pm0.20, Sf=1.09±0.33±0.08S_f=-1.09\pm0.33\pm0.08, Sfˉ=0.36±0.34±0.08S_{\bar{f}}=-0.36\pm0.34\pm0.08, where the uncertainties are statistical and systematic, respectively. Using these observables together with a recent measurement of the Bs0B^0_s mixing phase 2βs-2\beta_s leads to the first extraction of the CKM angle γ\gamma from Bs0DsK±B^0_s \rightarrow D^{\mp}_s K^{\pm} decays, finding γ\gamma = (11543+28_{-43}^{+28})^\circ modulo 180^\circ at 68% CL, where the error contains both statistical and systematic uncertainties

    Search for the lepton flavour violating decay tau(-) -> mu(-)mu(+)mu(-)

    Get PDF
    A search for the lepton flavour violating decay τμμ+μ\tau^-\rightarrow\mu^-\mu^+\mu^- is performed with the LHCb experiment. The data sample corresponds to an integrated luminosity of 1.0 fb1^{−1} of proton-proton collisions at a centre-of-mass energy of 7 TeV and 2.0 fb1^{−1} at 8 TeV. No evidence is found for a signal, and a limit is set at 90% confidence level on the branching fraction, B(τμμ+μ)<4.6×108\mathcal{B}(\tau^-\rightarrow\mu^-\mu^+\mu^-)<4.6\times10^{−8}.A search for the lepton flavour violating decay τ^{−} → μ^{−} μ+^{+} μ^{−} is performed with the LHCb experiment. The data sample corresponds to an integrated luminosity of 1.0 fb1^{−1} of proton-proton collisions at a centre-of-mass energy of 7 TeV and 2.0 fb1^{−1} at 8 TeV. No evidence is found for a signal, and a limit is set at 90% confidence level on the branching fraction, B(τμμ+μ)<4.6×108 \mathrm{\mathcal{B}}\left({\tau}^{-}\to {\mu}^{-}{\mu}^{+}{\mu}^{-}\right)<4.6\times {10}^{-8} .A search for the lepton flavour violating decay τμμ+μ\tau^-\to \mu^-\mu^+\mu^- is performed with the LHCb experiment. The data sample corresponds to an integrated luminosity of 1.0fb11.0\mathrm{\,fb}^{-1} of proton-proton collisions at a centre-of-mass energy of 7TeV7\mathrm{\,Te\kern -0.1em V} and 2.0fb12.0\mathrm{\,fb}^{-1} at 8TeV8\mathrm{\,Te\kern -0.1em V}. No evidence is found for a signal, and a limit is set at 90%90\% confidence level on the branching fraction, B(τμμ+μ)<4.6×108\mathcal{B}(\tau^-\to \mu^-\mu^+\mu^-) < 4.6 \times 10^{-8}

    Precise measurements of the properties of the B-1(5721)(0,+) and B-2*(5747)(0,+) states and observation of B-+,B-0 pi(-,+) mass structures

    Get PDF
    Invariant mass distributions of B+πB^+\pi^- and B0π+B^0\pi^+ combinations are investigated in order to study excited B mesons. The analysis is based on a data sample corresponding to 3.0fb13.0 fb^{-1} of pppp collision data, recorded by the LHCb detector at centre-of-mass energies of 7 and 8 TeV. Precise measurements of the masses and widths of the B1(5721)0,+B_1(5721)^{0,+} and B2(5747)0,+B_2^*(5747)^{0,+} states are reported. Clear enhancements, particularly prominent at high pion transverse momentum, are seen over background in the mass range 58505850-60006000 MeV in both B+πB^+\pi^- and B0π+B^0\pi^+ combinations. The structures are consistent with the presence of four excited B mesons, labelled BJ(5840)0,+B_J(5840)^{0,+} and BJ(5960)0,+B_J(5960)^{0,+}, whose masses and widths are obtained under different hypotheses for their quantum numbers.Invariant mass distributions of B+^{+} π^{−} and B0^{0} π+^{+} combinations are investigated in order to study excited B mesons. The analysis is based on a data sample corresponding to 3.0 fb1^{−1} of pp collision data, recorded by the LHCb detector at centre-of-mass energies of 7 and 8 TeV. Precise measurements of the masses and widths of the B1_{1}(5721)0,+^{0,+} and B2^{2}(5747)0,+^{0,+} states are reported. Clear enhancements, particularly prominent at high pion transverse momentum, are seen over background in the mass range 5850-6000 MeV in both B+^{+} π^{−} and B0^{0} π+^{+} combinations. The structures are consistent with the presence of four excited B mesons, labelled BJ_{J} (5840)0,+^{0,+} and BJ_{J} (5960)0,+^{0,+}, whose masses and widths are obtained under different hypotheses for their quantum numbers.Invariant mass distributions of B+pi- and B0pi+ combinations are investigated in order to study excited B mesons. The analysis is based on a data sample corresponding to 3.0 fb-1 of pp collision data, recorded by the LHCb detector at centre-of-mass energies of 7 and 8 TeV. Precise measurements of the masses and widths of the B_1(5721)^(0,+) and B_2*(5747)^(0,+) states are reported. Clear enhancements, particularly prominent at high pion transverse momentum, are seen over background in the mass range 5850--6000 MeV in both B+pi- and B0pi+ combinations. The structures are consistent with the presence of four excited B mesons, labelled B_J(5840)^(0,+) and B_J(5960)^(0,+), whose masses and widths are obtained under different hypotheses for their quantum numbers
    corecore