1,921 research outputs found

    Chemotherapy-Response Monitoring of Breast Cancer Patients Using Quantitative Ultrasound-Based Intra-Tumour Heterogeneities

    Get PDF
    © 2017 The Author(s). Anti-cancer therapies including chemotherapy aim to induce tumour cell death. Cell death introduces alterations in cell morphology and tissue micro-structures that cause measurable changes in tissue echogenicity. This study investigated the effectiveness of quantitative ultrasound (QUS) parametric imaging to characterize intra-tumour heterogeneity and monitor the pathological response of breast cancer to chemotherapy in a large cohort of patients (n = 100). Results demonstrated that QUS imaging can non-invasively monitor pathological response and outcome of breast cancer patients to chemotherapy early following treatment initiation. Specifically, QUS biomarkers quantifying spatial heterogeneities in size, concentration and spacing of acoustic scatterers could predict treatment responses of patients with cross-validated accuracies of 82 ± 0.7%, 86 ± 0.7% and 85 ± 0.9% and areas under the receiver operating characteristic (ROC) curve of 0.75 ± 0.1, 0.80 ± 0.1 and 0.89 ± 0.1 at 1, 4 and 8 weeks after the start of treatment, respectively. The patients classified as responders and non-responders using QUS biomarkers demonstrated significantly different survivals, in good agreement with clinical and pathological endpoints. The results form a basis for using early predictive information on survival-linked patient response to facilitate adapting standard anti-cancer treatments on an individual patient basis

    Differential branching fraction and angular analysis of the decay B0→K∗0ÎŒ+Ό−

    Get PDF
    The angular distribution and differential branching fraction of the decay B 0→ K ∗0 ÎŒ + ÎŒ − are studied using a data sample, collected by the LHCb experiment in pp collisions at s√=7 TeV, corresponding to an integrated luminosity of 1.0 fb−1. Several angular observables are measured in bins of the dimuon invariant mass squared, q 2. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q20=4.9±0.9GeV2/c4 , where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions

    Measurement of the relative rate of prompt χc0, χc1 and χc2 production at √s=7TeV

    Get PDF
    Prompt production of charmonium χc0, χc1 and χc2 mesons is studied using proton-proton collisions at the LHC at a centre-of-mass energy of √s=7TeV. The χc mesons are identified through their decay to J/ÏˆÎł, with J/ψ→Ό+mu− using photons that converted in the detector. A data sample, corresponding to an integrated luminosity of 1.0fb−1 collected by the LHCb detector, is used to measure the relative prompt production rate of χc1 and χc2 in the rapidity range 2.0<y<4.5 as a function of the J/ψ transverse momentum from 3 to 20 GeV/c. First evidence for χc0 meson production at a hadron collider is also presented

    Observation of the decay Bc→J/ψK+K−π+B_c \rightarrow J/\psi K^+ K^- \pi^+

    Get PDF
    The decay Bc→J/ψK+K−π+B_c\rightarrow J/\psi K^+ K^- \pi^+ is observed for the first time, using proton-proton collisions collected with the LHCb detector corresponding to an integrated luminosity of 3fb−1^{-1}. A signal yield of 78±1478\pm14 decays is reported with a significance of 6.2 standard deviations. The ratio of the branching fraction of \B_c \rightarrow J/\psi K^+ K^- \pi^+ decays to that of Bc→J/ψπ+B_c \rightarrow J/\psi \pi^+ decays is measured to be 0.53±0.10±0.050.53\pm 0.10\pm0.05, where the first uncertainty is statistical and the second is systematic.Comment: 18 pages, 2 figure

    Search for the lepton-flavor-violating decays Bs0→e±Ό∓ and B0→e±Ό∓

    Get PDF
    A search for the lepton-flavor-violating decays Bs0→e±Ό∓ and B0→e±Ό∓ is performed with a data sample, corresponding to an integrated luminosity of 1.0  fb-1 of pp collisions at √s=7  TeV, collected by the LHCb experiment. The observed number of Bs0→e±Ό∓ and B0→e±Ό∓ candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be B(Bs0→e±Ό∓)101  TeV/c2 and MLQ(B0→e±Ό∓)>126  TeV/c2 at 95% C.L., and are a factor of 2 higher than the previous bounds

    Observation of associated production of a ZZ boson with a DD meson in the~forward region

    Get PDF
    A search for associated production of a ZZ boson with an open charm meson is presented using a data sample, corresponding to an integrated luminosity of 1.0 fb−‘1.0\,\mathrm{fb}^{-`} of proton--proton collisions at a centre-of-mass energy of 7\,TeV, collected by the LHCb experiment. %% Seven candidate events for associated production of a ZZ boson with a D0D^0 meson and four candidate events for a ZZ boson with a D+D^+ meson are observed with a combined significance of 5.1standard deviations. The production cross-sections in the forward region are measured to be σZ→Ό+ÎŒâˆ’â€‰âŁ,D0=2.50±1.12±0.22pb\sigma_{Z\rightarrow\mu^+\mu^-\!,D^0} = 2.50\pm1.12\pm0.22pb σZ→Ό+ÎŒâˆ’â€‰âŁ,D+=0.44±0.23±0.03pb,\sigma_{Z\rightarrow\mu^+\mu^-\!,D^+} = 0.44\pm0.23\pm0.03pb, where the first uncertainty is statistical and the second systematic.Comment: 18 pages, 2 figure

    Model-independent search for CP violation in D0→K−K+π−π+ and D0→π−π+π+π− decays

    Get PDF
    A search for CP violation in the phase-space structures of D0 and View the MathML source decays to the final states K−K+π−π+ and π−π+π+π− is presented. The search is carried out with a data set corresponding to an integrated luminosity of 1.0 fb−1 collected in 2011 by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. For the K−K+π−π+ final state, the four-body phase space is divided into 32 bins, each bin with approximately 1800 decays. The p-value under the hypothesis of no CP violation is 9.1%, and in no bin is a CP asymmetry greater than 6.5% observed. The phase space of the π−π+π+π− final state is partitioned into 128 bins, each bin with approximately 2500 decays. The p-value under the hypothesis of no CP violation is 41%, and in no bin is a CP asymmetry greater than 5.5% observed. All results are consistent with the hypothesis of no CP violation at the current sensitivity

    Measurements of the B+B^+, B0B^0, Bs0B_s^0 meson and Λb0\Lambda_b^0 baryon lifetimes

    Get PDF
    Measurements of bb-hadron lifetimes are reported using pppp collision data, corresponding to an integrated luminosity of 1.0fb−1^{-1}, collected by the LHCb detector at a centre-of-mass energy of 77Tev. Using the exclusive decays B+→J/ψK+B^+\to J/\psi K^+, B0→J/ψK∗(892)0B^0\to J/\psi K^*(892)^0, B0→J/ψKS0B^0\to J/\psi K^0_{\rm S}, Λb0→J/ψΛ\Lambda_b^0\to J/\psi \Lambda and Bs0→J/ψϕB^0_s\to J/\psi \phi the average decay times in these modes are measured to be τB+→J/ψK+\tau_{B^+\to J/\psi K^+} = 1.637±1.637 \pm 0.004 ±\pm 0.003 ps, τB0→J/ψK∗(892)0\tau_{B^0\to J/\psi K^*(892)^0} = 1.524±1.524 \pm 0.006 ±\pm 0.004 ps, τB0→J/ψKS0\tau_{B^0\to J/\psi K^0_{\rm S}} = 1.499±1.499 \pm 0.013 ±\pm 0.005 ps, τΛb0→J/ψΛ\tau_{\Lambda_b^0\to J/\psi \Lambda} = 1.415±1.415 \pm 0.027 ±\pm 0.006 ps and τBs0→J/ψϕ\tau_{B^0_s\to J/\psi \phi} = 1.480±1.480 \pm 0.011 ±\pm 0.005 ps, where the first uncertainty is statistical and the second is systematic. These represent the most precise lifetime measurements in these decay modes. In addition, ratios of these lifetimes, and the ratio of the decay-width difference, ΔΓd\Delta\Gamma_d, to the average width, Γd\Gamma_d, in the B0B^0 system, ΔΓd/Γd=−0.044±0.025±0.011\Delta \Gamma_d/\Gamma_d = -0.044 \pm 0.025 \pm 0.011, are reported. All quantities are found to be consistent with Standard Model expectations.Comment: 28 pages, 4 figures. Updated reference

    Observations of BÂșs→ψ(2S)η and BÂș(s)→ψ(2S)π+π- decays

    Get PDF
    First observations of the B0s →ψ(2S)η, B0 →ψ(2S)π + π − and B0s →ψ(2S)π + π − decays are made using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in proton–proton collisions at a centre-of-mass energy of √ s = 7 TeV. The ratios of the branching fractions of each of the ψ(2S) modes with respect to the corresponding J/ψ decays are B(B0s →ψ(2S)η) Ă· B(B0s →J/ψη) = 0.83± 0.14 (stat)±0.12 (syst) ±0.02 (B), ; B(B0→ψ(2S)π + π − ) Ă· B(B0→J/ψπ + π − ) = 0.56± 0.07 (stat)±0.05 (syst)± 0.01 (B), ; B(B0s →ψ(2S)π + π − ) Ă· B(B0s →J/ψπ + π − ) = 0.34± 0.04 (stat)±0.03 (syst)± 0.01 (B), where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the J/ψ and ψ(2S) meson decays

    Observation of the decay B+c→BÂșsπ+

    Get PDF
    The result of a search for the decay B+c→BÂșsπ+ is presented, using the BÂșs→Ds-π+ and BÂșs→J/ψϕ channels. The analysis is based on a data sample of pp collisions collected with the LHCb detector, corresponding to an integrated luminosity of 1  fb-1 taken at a center-of-mass energy of 7 TeV, and 2  fb-1 taken at 8 TeV. The decay B+c→BÂșsπ+ is observed with significance in excess of 5 standard deviations independently in both decay channels. The measured product of the ratio of cross sections and branching fraction is [σ(Bc+)/σ(BÂșs)]×B(Bc+→BÂșsπ+)=[2.37±0.31 (stat)±0.11 (syst)-0.13+0.17(τBc+)]×10-3, in the pseudorapidity range 2<η(B)<5, where the first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty on the Bc+ lifetime. This is the first observation of a B meson decaying to another B meson via the weak interaction
    • 

    corecore