616 research outputs found

    Search for the lepton-flavour violating decays B-0 -> K-*0 mu(+/-)e(-/+) and B-s(0)-> phi mu(+/-)e(-/+)

    No full text
    A search for the lepton-flavour violating decays B 0 → K *0 μ ± e ∓ and Bs0 → φμ ± e ∓ is presented, using proton-proton collision data collected by the LHCb detector at the LHC, corresponding to an integrated luminosity of 9 fb −1. No significant signals are observed and upper limits of B(B0→K∗0μ+e−)<5.7×10−9(6.9×10−9),B(B0→K∗0μ−e+)<6.8×10−9(7.9×10−9),B(B0→K∗0μ±e∓)<10.1×10−9(11.7×10−9),B(Bs0→φμ±e∓)<16.0×10−9(19.8×10−9) are set at 90% (95%) confidence level. These results constitute the world’s most stringent limits to date, with the limit on the decay Bs0 → φμ ± e ∓ the first being set. In addition, limits are reported for scalar and left-handed lepton-flavour violating New Physics scenarios. [Figure not available: see fulltext.]

    Measurements of the branching fraction ratio B(φ→μ+μ−)/B(φ→e+e−) with charm meson decays

    No full text
    Measurements of the branching fraction ratio B(φ→μ+μ−)/B(φ→e+e−) with Ds+→π+φ and D+→ π+φ decays, denoted Rφπs and Rφπd, are presented. The analysis is performed using a dataset corresponding to an integrated luminosity of 5.4 fb−1 of pp collision data collected with the LHCb experiment. The branching fractions are normalised with respect to the B+ → K+J/ψ(→ e+e−) and B+ → K+J/ψ(→ μ+μ−) decay modes. The combination of the results yields (Formula presented.) The result is compatible with previous measurements of the φ → l+l− branching fractions and predictions based on the Standard Model

    Measurements of the branching fraction ratio B(ϕ → μ+μ−) / B(ϕ → e+e−) with charm meson decays

    No full text
    Measurements of the branching fraction ratio B(ϕ → μ+μ−) / B(ϕ → e+e−) with Ds+→π+ϕ and D+→ π+ϕ decays, denoted Rϕπs and Rϕπd, are presented. The analysis is performed using a dataset corresponding to an integrated luminosity of 5.4 fb−1 of pp collision data collected with the LHCb experiment. The branching fractions are normalised with respect to the B+ → K+J/ψ(→ e+e−) and B+ → K+J/ψ(→ μ+μ−) decay modes. The combination of the results yieldsRϕπ=1.022±0.012stat±0.048syst. The result is compatible with previous measurements of the ϕ → ℓ+ℓ− branching fractions and predictions based on the Standard Model

    First measurement of the CP-violating phase in B-s(0) -> J/Psi (-> e(+) e(-))phi decays

    No full text
    A flavour-tagged time-dependent angular analysis of Bs0→J/ψφ decays is presented where the J/ ψ meson is reconstructed through its decay to an e+e- pair. The analysis uses a sample of pp collision data recorded with the LHCb experiment at centre-of-mass energies of 7 and 8 ,Te V , corresponding to an integrated luminosity of 3 ,fb - 1. The CP-violating phase and lifetime parameters of the Bs0 system are measured to be φs= 0.00 ± 0.28 ± 0.07 ,rad , Δ Γ s= 0.115 ± 0.045 ± 0.011 ,ps - 1 and Γ s= 0.608 ± 0.018 ± 0.012 ,ps - 1 where the first uncertainty is statistical and the second systematic. This is the first time that CP-violating parameters are measured in the Bs0→J/ψφ decay with an e+e- pair in the final state. The results are consistent with previous measurements in other channels and with the Standard Model predictions

    Search for the lepton-flavour violating decays B 0 → K *0 μ ± e ∓ and Bs0 → φμ ± e ∓

    No full text
    A search for the lepton-flavour violating decays B 0 → K *0 μ ± e ∓ and Bs0 → φμ ± e ∓ is presented, using proton-proton collision data collected by the LHCb detector at the LHC, corresponding to an integrated luminosity of 9 fb −1. No significant signals are observed and upper limits of B(B0→K∗0μ+e−)<5.7×10−9(6.9×10−9),B(B0→K∗0μ−e+)<6.8×10−9(7.9×10−9),B(B0→K∗0μ±e∓)<10.1×10−9(11.7×10−9),B(Bs0→φμ±e∓)<16.0×10−9(19.8×10−9) are set at 90% (95%) confidence level. These results constitute the world’s most stringent limits to date, with the limit on the decay Bs0 → φμ ± e ∓ the first being set. In addition, limits are reported for scalar and left-handed lepton-flavour violating New Physics scenarios

    Angular analysis of B0K0e+eB^0\rightarrow K^{*0}e^{+}e^{-} decays

    No full text
    International audienceAn angular analysis of B0K0e+eB^0\rightarrow K^{*0}e^{+}e^{-} decays is presented using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb1^{-1}. The analysis is performed in the region of the dilepton invariant mass squared of 1.1-6.0 GeV2/c4^{2}/c^{4}. In addition, a test of lepton flavour universality is performed by comparing the obtained angular observables with those measured in B0K0μ+μB^0\rightarrow K^{*0}\mu^{+}\mu^{-} decays. In general, the angular observables are found to be consistent with the Standard Model expectations as well as with global analyses of other bs+b \rightarrow s \ell^{+} \ell^{-} processes, where \ell is either a muon or an electron. No sign of lepton-flavour-violating effects is observed

    Search for the lepton-flavour violating decays B0K0μ±eB^0 \to K^{*0} \mu^\pm e^\mp and Bs0ϕμ±eB_s^0 \to \phi \mu^\pm e^\mp

    No full text
    A search for the lepton-flavour violating decays B0K0μ±eB^0 \to K^{*0} \mu^\pm e^\mp and Bs0ϕμ±eB_s^0 \to \phi \mu^\pm e^\mp is presented, using proton-proton collision data collected by the LHCb detector at the LHC, corresponding to an integrated luminosity of 9fb19\,\text{fb}^{-1}. No significant signals are observed and upper limits of \begin{align} {\cal B}( B^0 \to K^{*0} \mu^+ e^- ) &< \phantom{1}5.7\times 10^{-9}~(6.9\times 10^{-9}),\newline {\cal B}( B^0 \to K^{*0} \mu^- e^+ ) &< \phantom{1}6.8\times 10^{-9}~(7.9\times 10^{-9}),\newline {\cal B}( B^0 \to K^{*0} \mu^\pm e^\mp ) &< 10.1\times 10^{-9}~(11.7\times 10^{-9}),\newline {\cal B}( B_s^0 \to \phi \mu^\pm e^\mp ) &< 16.0\times 10^{-9}~(19.8\times 10^{-9}) \end{align} are set at 90% (95%)90\%~(95\%) confidence level. These results constitute the world's most stringent limits to date, with the limit on the decay Bs0ϕμ±eB_s^0 \to \phi \mu^\pm e^\mp the first being set. In addition, limits are reported for scalar and left-handed lepton-flavour violating New Physics scenarios.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-008.html (LHCb public pages

    Measurements of the branching fraction ratio B(φ→μ+μ−)/B(φ→e+e−) with charm meson decays

    No full text
    Measurements of the branching fraction ratio B(φ→μ+μ−)/B(φ→e+e−) with Ds+→π+φ and D+→ π+φ decays, denoted Rφπs and Rφπd, are presented. The analysis is performed using a dataset corresponding to an integrated luminosity of 5.4 fb−1 of pp collision data collected with the LHCb experiment. The branching fractions are normalised with respect to the B+ → K+J/ψ(→ e+e−) and B+ → K+J/ψ(→ μ+μ−) decay modes. The combination of the results yields (Formula presented.) The result is compatible with previous measurements of the φ → l+l− branching fractions and predictions based on the Standard Model

    Constraints on the photon polarisation in bsγb \to s \gamma transitions using Bs0ϕe+eB_s^0\to \phi e^+ e^- decays

    No full text
    An angular analysis of the Bs0ϕe+eB_s^0 \rightarrow \phi e^+e^- decay is performed using the proton-proton collision dataset collected between 2011 and 2018 by the LHCb experiment, corresponding to an integrated luminosity of 9fb19\,{\rm fb}^{-1} at centre-of-mass energies of 7, 8 and 13TeV13\,{\rm TeV}. The analysis is performed in the very low dielectron invariant mass-squared region between 0.00090.0009 and 0.2615GeV2 ⁣/c40.2615\,{\rm GeV}^2\!/c^4. The longitudinal polarisation fraction of the ϕ\phi meson is measured to be less than 11.5%11.5\% at 90%90\% confidence level. The ATReC ⁣PA_{\mathrm{T}}^{\mathcal{R}e C\!P} observable, which is related to the lepton forward-backward asymmetry, is measured to be 0.116±0.155±0.0060.116 \pm 0.155 \pm 0.006, where the first uncertainty is statistical and the second systematic. The transverse asymmetries, AT(2)A_{\mathrm{T}}^{(2)} and ATImC ⁣PA_{\mathrm{T}}^{\mathcal{I}m C\!P} , which are sensitive to the virtual photon polarisation, are found to be 0.045±0.235±0.014-0.045 \pm 0.235 \pm 0.014 and 0.002±0.247±0.0160.002 \pm 0.247 \pm 0.016, respectively. The results are consistent with Standard Model predictions.An angular analysis of the Bs0 {B}_s^0 → ϕe+^{+}e^{−} decay is performed using the proton-proton collision dataset collected between 2011 and 2018 by the LHCb experiment, corresponding to an integrated luminosity of 9 fb1^{−1} at centre-of-mass energies of 7, 8 and 13 TeV. The analysis is performed in the very low dielectron invariant mass-squared region between 0.0009 and 0.2615 GeV2^{2}/c4^{4}. The longitudinal polarisation fraction of the ϕ meson is measured to be less than 11.5% at 90% confidence level. The ATReCP {A}_{\textrm{T}}^{\mathcal{R} eCP} observable, which is related to the lepton forward-backward asymmetry, is measured to be 0.116 ± 0.155 ± 0.006, where the first uncertainty is statistical and the second systematic. The transverse asymmetries, AT(2) {A}_{\textrm{T}}^{(2)} and ATImCP {A}_{\textrm{T}}^{\mathcal{I} mCP} , which are sensitive to the virtual photon polarisation, are found to be −0.045 ± 0.235 ± 0.014 and 0.002 ± 0.247 ± 0.016, respectively. The results are consistent with Standard Model predictions.[graphic not available: see fulltext]An angular analysis of the Bs0ϕe+eB_s^0 \rightarrow \phi e^+e^- decay is performed using the proton-proton collision dataset collected between 2011 and 2018 by the LHCb experiment, corresponding to an integrated luminosity of 9fb19\,{\rm fb}^{-1} at centre-of-mass energies of 7, 8 and 13TeV13\,{\rm TeV}. The analysis is performed in the very low dielectron invariant mass-squared region between 0.00090.0009 and 0.2615GeV2 ⁣/c40.2615\,{\rm GeV}^2\!/c^4. The longitudinal polarisation fraction of the ϕ\phi meson is measured to be less than 11.5%11.5\% at 90%90\% confidence level. The ATReC ⁣PA_{\mathrm{T}}^{\mathcal{R}e C\!P} observable, which is related to the lepton forward-backward asymmetry, is measured to be 0.116±0.155±0.0060.116 \pm 0.155 \pm 0.006, where the first uncertainty is statistical and the second systematic. The transverse asymmetries, AT(2)A_{\mathrm{T}}^{(2)} and ATImC ⁣PA_{\mathrm{T}}^{\mathcal{I}m C\!P}, which are sensitive to the virtual photon polarisation, are found to be 0.045±0.235±0.014-0.045 \pm 0.235 \pm 0.014 and 0.002±0.247±0.0160.002 \pm 0.247 \pm 0.016, respectively. The results are consistent with Standard Model predictions

    First measurement of the C ⁣PC\!P-violating phase in Bs0 ⁣J/ψ(e+e{{B} ^0_{s}} \!\rightarrow {{J /\psi }} (\rightarrow e ^+e ^-)ϕ\phi decays

    No full text
    International audienceA flavour-tagged time-dependent angular analysis of Bs0 ⁣J/ψϕ{{B} ^0_{s}} \!\rightarrow {{J /\psi }} \phi decays is presented where the J/ψ{J /\psi } meson is reconstructed through its decay to an e+ee ^+e ^- pair. The analysis uses a sample of pp collision data recorded with the LHCb experiment at centre-of-mass energies of 7 and 8Te V8\text {\,Te V} , corresponding to an integrated luminosity of 3fb13 \text {\,fb} ^{-1} . The C ⁣PC\!P-violating phase and lifetime parameters of the Bs0{B} ^0_{s} system are measured to be ϕs=0.00±0.28±0.07rad{\phi _{{s}}} =0.00\pm 0.28\pm 0.07\text {\,rad}, ΔΓs=0.115±0.045±0.011ps1{\Delta \Gamma _{{s}}} =0.115\pm 0.045\pm 0.011\text {\,ps} ^{-1} and Γs=0.608±0.018±0.012ps1{\Gamma _{{s}}} =0.608\pm 0.018\pm 0.012\text {\,ps} ^{-1} where the first uncertainty is statistical and the second systematic. This is the first time that C ⁣PC\!P-violating parameters are measured in the Bs0 ⁣J/ψϕ{{B} ^0_{s}} \!\rightarrow {{J /\psi }} \phi decay with an e+ee ^+e ^- pair in the final state. The results are consistent with previous measurements in other channels and with the Standard Model predictions
    corecore