3,723 research outputs found

    Making the Case for Diversity in Philanthropy

    Get PDF
    While many foundations have long sought to become more inclusive as a logical extension of their missions, the business case for incorporating diversity has renewed interest in understanding how diversity can also enhance the effectiveness of philanthropic organizations. Because prior movements to increase diversity in philanthropy have focused on moral, rather than operational, arguments and because the field lacks an easy way to measure outcomes, strong evaluation measures of diversity's impacts on philanthropic activity have not been developed. Numerous studies from the corporate sphere, however, suggest that greater inclusiveness may improve an organization's processes and outcomes. Many philanthropic experts and practitioners believe that these gains may apply to grantmaking institutions as well as businesses.

    Measurement of the Bs0→J/ψηB_{s}^{0} \rightarrow J/\psi \eta lifetime

    Get PDF
    Using a data set corresponding to an integrated luminosity of 3fb−13 fb^{-1}, collected by the LHCb experiment in pppp collisions at centre-of-mass energies of 7 and 8 TeV, the effective lifetime in the Bs0→J/ψηB^0_s \rightarrow J/\psi \eta decay mode, τeff\tau_{\textrm{eff}}, is measured to be τeff=1.479±0.034 (stat)±0.011 (syst)\tau_{\textrm{eff}} = 1.479 \pm 0.034~\textrm{(stat)} \pm 0.011 ~\textrm{(syst)} ps. Assuming CPCP conservation, τeff\tau_{\textrm{eff}} corresponds to the lifetime of the light Bs0B_s^0 mass eigenstate. This is the first measurement of the effective lifetime in this decay mode.Comment: 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-2016-017.htm

    Measurement of the mass and lifetime of the Ωb−\Omega_b^- baryon

    Get PDF
    A proton-proton collision data sample, corresponding to an integrated luminosity of 3 fb−1^{-1} collected by LHCb at s=7\sqrt{s}=7 and 8 TeV, is used to reconstruct 63±963\pm9 Ωb−→Ωc0π−\Omega_b^-\to\Omega_c^0\pi^-, Ωc0→pK−K−π+\Omega_c^0\to pK^-K^-\pi^+ decays. Using the Ξb−→Ξc0π−\Xi_b^-\to\Xi_c^0\pi^-, Ξc0→pK−K−π+\Xi_c^0\to pK^-K^-\pi^+ decay mode for calibration, the lifetime ratio and absolute lifetime of the Ωb−\Omega_b^- baryon are measured to be \begin{align*} \frac{\tau_{\Omega_b^-}}{\tau_{\Xi_b^-}} &= 1.11\pm0.16\pm0.03, \\ \tau_{\Omega_b^-} &= 1.78\pm0.26\pm0.05\pm0.06~{\rm ps}, \end{align*} where the uncertainties are statistical, systematic and from the calibration mode (for τΩb−\tau_{\Omega_b^-} only). A measurement is also made of the mass difference, mΩb−−mΞb−m_{\Omega_b^-}-m_{\Xi_b^-}, and the corresponding Ωb−\Omega_b^- mass, which yields \begin{align*} m_{\Omega_b^-}-m_{\Xi_b^-} &= 247.4\pm3.2\pm0.5~{\rm MeV}/c^2, \\ m_{\Omega_b^-} &= 6045.1\pm3.2\pm 0.5\pm0.6~{\rm MeV}/c^2. \end{align*} These results are consistent with previous measurements.Comment: 11 pages, 5 figures, 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-2016-008.htm

    Observation of an Excited Bc+ State

    Get PDF
    Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+Îł decay following Bc∗(2S31)+→Bc∗(1S31)+π+π-. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date

    Constraints on the unitarity triangle angle Îł\gamma from Dalitz plot analysis of B0→DK+π−B^0 \to D K^+ \pi^- decays

    Get PDF
    The first study is presented of CP violation with an amplitude analysis of the Dalitz plot of B0→DK+π−B^0 \to D K^+ \pi^- decays, with D→K+π−D \to K^+ \pi^-, K+K−K^+ K^- and π+π−\pi^+ \pi^-. The analysis is based on a data sample corresponding to 3.0 fb−13.0\,{\rm fb}^{-1} of pppp collisions collected with the LHCb detector. No significant CP violation effect is seen, and constraints are placed on the angle Îł\gamma of the unitarity triangle formed from elements of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. Hadronic parameters associated with the B0→DK∗(892)0B^0 \to D K^*(892)^0 decay are determined for the first time. These measurements can be used to improve the sensitivity to Îł\gamma of existing and future studies of the B0→DK∗(892)0B^0 \to D K^*(892)^0 decay.Comment: 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-2015-059.html; updated to correct figure 9 (numerical results unchanged

    A new algorithm for identifying the flavour of Bs0B_s^0 mesons at LHCb

    Get PDF
    A new algorithm for the determination of the initial flavour of Bs0B_s^0 mesons is presented. The algorithm is based on two neural networks and exploits the bb hadron production mechanism at a hadron collider. The first network is trained to select charged kaons produced in association with the Bs0B_s^0 meson. The second network combines the kaon charges to assign the Bs0B_s^0 flavour and estimates the probability of a wrong assignment. The algorithm is calibrated using data corresponding to an integrated luminosity of 3 fb−1^{-1} collected by the LHCb experiment in proton-proton collisions at 7 and 8 TeV centre-of-mass energies. The calibration is performed in two ways: by resolving the Bs0B_s^0-Bˉs0\bar{B}_s^0 flavour oscillations in Bs0→Ds−π+B_s^0 \to D_s^- \pi^+ decays, and by analysing flavour-specific Bs2∗(5840)0→B+K−B_{s 2}^{*}(5840)^0 \to B^+ K^- decays. The tagging power measured in Bs0→Ds−π+B_s^0 \to D_s^- \pi^+ decays is found to be (1.80±0.19(stat)±0.18(syst))(1.80 \pm 0.19({\rm stat}) \pm 0.18({\rm syst}))\%, which is an improvement of about 50\% compared to a similar algorithm previously used in the LHCb experiment.Comment: 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-2015-056.htm

    Model-independent evidence for J/ψpJ/\psi p contributions to Λb0→J/ψpK−\Lambda_b^0\to J/\psi p K^- decays

    Get PDF
    The data sample of Λb0→J/ψpK−\Lambda_b^0\to J/\psi p K^- decays acquired with the LHCb detector from 7 and 8~TeV pppp collisions, corresponding to an integrated luminosity of 3 fb−1^{-1}, is inspected for the presence of J/ψpJ/\psi p or J/ψK−J/\psi K^- contributions with minimal assumptions about K−pK^- p contributions. It is demonstrated at more than 9 standard deviations that Λb0→J/ψpK−\Lambda_b^0\to J/\psi p K^- decays cannot be described with K−pK^- p contributions alone, and that J/ψpJ/\psi p contributions play a dominant role in this incompatibility. These model-independent results support the previously obtained model-dependent evidence for Pc+→J/ψpP_c^+\to J/\psi p charmonium-pentaquark states in the same data sample.Comment: 21 pages, 12 figures (including the supplemental section added at the end

    Observation of the Bs0→J/ψϕϕB_s^0 \rightarrow J/\psi \phi \phi decay

    Get PDF
    The Bs0→J/ψϕϕB_s^0 \rightarrow J/\psi \phi \phi decay is observed in pppp collision data corresponding to an integrated luminosity of 3 fb−1^{-1} recorded by the LHCb detector at centre-of-mass energies of 7 TeV and 8 TeV. This is the first observation of this decay channel, with a statistical significance of 15 standard deviations. The mass of the Bs0B_s^0 meson is measured to be 5367.08 ± 0.38 ± 0.155367.08\,\pm \,0.38\,\pm\, 0.15 MeV/c2^2. The branching fraction ratio B(Bs0→J/ψϕϕ)/B(Bs0→J/ψϕ)\mathcal{B}(B_s^0 \rightarrow J/\psi \phi \phi)/\mathcal{B}(B_s^0 \rightarrow J/\psi \phi) is measured to be 0.0115\,\pm\, 0.0012\, ^{+0.0005}_{-0.0009}. In both cases, the first uncertainty is statistical and the second is systematic. No evidence for non-resonant Bs0→J/ψϕK+K−B_s^0 \rightarrow J/\psi \phi K^+ K^- or Bs0→J/ψK+K−K+K−B_s^0 \rightarrow J/\psi K^+ K^- K^+ K^- decays is found.Comment: 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-2015-033.htm

    Bose-Einstein correlations of same-sign charged pions in the forward region in pp collisions at √s=7 TeV

    Get PDF
    Bose-Einstein correlations of same-sign charged pions, produced in protonproton collisions at a 7 TeV centre-of-mass energy, are studied using a data sample collected by the LHCb experiment. The signature for Bose-Einstein correlations is observed in the form of an enhancement of pairs of like-sign charged pions with small four-momentum difference squared. The charged-particle multiplicity dependence of the Bose-Einstein correlation parameters describing the correlation strength and the size of the emitting source is investigated, determining both the correlation radius and the chaoticity parameter. The measured correlation radius is found to increase as a function of increasing charged-particle multiplicity, while the chaoticity parameter is seen to decreas
    • 

    corecore