262 research outputs found

    Physics case for an LHCb Upgrade II - Opportunities in flavour physics, and beyond, in the HL-LHC era

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    The LHCb Upgrade II will fully exploit the flavour-physics opportunities of the HL-LHC, and study additional physics topics that take advantage of the forward acceptance of the LHCb spectrometer. The LHCb Upgrade I will begin operation in 2020. Consolidation will occur, and modest enhancements of the Upgrade I detector will be installed, in Long Shutdown 3 of the LHC (2025) and these are discussed here. The main Upgrade II detector will be installed in long shutdown 4 of the LHC (2030) and will build on the strengths of the current LHCb experiment and the Upgrade I. It will operate at a luminosity up to 2×1034 cm−2s−1, ten times that of the Upgrade I detector. New detector components will improve the intrinsic performance of the experiment in certain key areas. An Expression Of Interest proposing Upgrade II was submitted in February 2017. The physics case for the Upgrade II is presented here in more depth. CP-violating phases will be measured with precisions unattainable at any other envisaged facility. The experiment will probe b → sl+l−and b → dl+l− transitions in both muon and electron decays in modes not accessible at Upgrade I. Minimal flavour violation will be tested with a precision measurement of the ratio of B(B0 → ÎŒ+Ό−)/B(Bs → ÎŒ+Ό−). Probing charm CP violation at the 10−5 level may result in its long sought discovery. Major advances in hadron spectroscopy will be possible, which will be powerful probes of low energy QCD. Upgrade II potentially will have the highest sensitivity of all the LHC experiments on the Higgs to charm-quark couplings. Generically, the new physics mass scale probed, for fixed couplings, will almost double compared with the pre-HL-LHC era; this extended reach for flavour physics is similar to that which would be achieved by the HE-LHC proposal for the energy frontier

    LHCb upgrade software and computing : technical design report

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    This document reports the Research and Development activities that are carried out in the software and computing domains in view of the upgrade of the LHCb experiment. The implementation of a full software trigger implies major changes in the core software framework, in the event data model, and in the reconstruction algorithms. The increase of the data volumes for both real and simulated datasets requires a corresponding scaling of the distributed computing infrastructure. An implementation plan in both domains is presented, together with a risk assessment analysis

    Search Method Based on Figurative Indexation of Folksonomic Features of Graphic Files

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    In this paper the search method based on usage of figurative indexation of folksonomic characteristics of graphical files is described. The method takes into account extralinguistic information, is based on using a model of figurative thinking of humans. The paper displays the creation of a method of searching image files based on their formal, including folksonomical clues

    Expression of Interest for a Phase-II LHCb Upgrade: Opportunities in flavour physics, and beyond, in the HL-LHC era

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    https://cds.cern.ch/record/224431

    Expression of Interest for a Phase-II LHCb Upgrade: Opportunities in flavour physics, and beyond, in the HL-LHC era

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    A Phase-II Upgrade is proposed for the LHCb experiment in order to take full advantage of the flavour-physics opportunities at the HL-LHC, and other topics that can be studied with a forward spectrometer. This Upgrade, which will be installed in Long Shutdown 4 of the LHC (2030), will build on the strengths of the current experiment and the Phase-I Upgrade, but will consist of re-designed sub-systems that can operate at a luminosity of 2×1034cm−2s−1, ten times that of the Phase-I Upgrade detector. New and improved detector components will increase the intrinsic performance of the experiment in certain key areas. In particular the installation of a tungsten sampling electromagnetic calorimeter will widen LHCb's capabilities for decays involving π0 and η mesons, electrons, and photons from loop-level penguin processes. The physics motivation is presented, and the prospects for operating the LHCb Interaction Point at high luminosity are assessed. The challenges for the detector are described and possible solutions are discussed. Finally, the key R\&D areas are summarised, together with a set of initial modifications suitable for implementation during Long Shutdown 3 (2024--2026)

    Measurement of the branching fraction and CPCP asymmetry in B+→J/ψρ+B^{+}\rightarrow J/\psi \rho^{+} decays

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    International audienceThe branching fraction and direct C ⁣PC\!P asymmetry of the decay B+ ⁣→J/ψρ+{{{B} ^+}} \!\rightarrow {{J /\psi }} {{\rho } ^+} are measured using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV, corresponding to a total integrated luminosity of 3   fb −1\,\text{ fb }^{-1} . The following results are obtained: B(B+ ⁣→J/ψρ+)=(3.81+0.25−0.24±0.35)×10−5,AC ⁣P(B+ ⁣→J/ψρ+)=−0.045+0.056−0.057±0.008,\begin{aligned} \mathcal {B}({{B} ^+} \!\rightarrow {{J /\psi }} {{\rho } ^+} )&= (3.81^{+0.25-0.24} \pm 0.35) \times 10^{-5},\\ \mathcal {A}^{{C\!P}} ({{B} ^+} \!\rightarrow {{J /\psi }} {{\rho } ^+} )&= -0.045^{+0.056-0.057} \pm 0.008, \end{aligned} where the first uncertainties are statistical and the second systematic. Both measurements are the most precise to date

    Amplitude analysis of the B(s)0→K∗0K‟∗0B^0_{(s)} \to K^{*0} \overline{K}^{*0} decays and measurement of the branching fraction of the B0→K∗0K‟∗0B^0 \to K^{*0} \overline{K}^{*0} decay

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    International audienceThe B0→K∗0K‟∗0 {B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} and Bs0→K∗0K‟∗0 {B}_s^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} decays are studied using proton-proton collision data corresponding to an integrated luminosity of 3 fb−1^{−1}. An untagged and timeintegrated amplitude analysis of B_{( s}_{)}^{0}  → (K+^{+}π−^{−})(K−^{−}π+^{+}) decays in two-body invariant mass regions of 150 MeV/c2^{2} around the K∗0^{∗0} mass is performed. A stronger longitudinal polarisation fraction in the B0→K∗0K‟∗0 {B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} decay, fL_{L} = 0.724 ± 0.051 (stat) ± 0.016 (syst), is observed as compared to fL_{L} = 0.240 ± 0.031 (stat) ± 0.025 (syst) in the Bs0→K∗0K‟∗0 {B}_s^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0} decay. The ratio of branching fractions of the two decays is measured and used to determine B(B0→K∗0K‟∗0)=(8.0±0.9(stat)±0.4(syst))×10−7 \mathrm{\mathcal{B}}\left({B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0}\right)=\left(8.0\pm 0.9\left(\mathrm{stat}\right)\pm 0.4\left(\mathrm{syst}\right)\right)\times {10}^{-7}
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