69 research outputs found

    Study of Bc+B_c^+ decays to the K+Kπ+K^+K^-\pi^+ final state and evidence for the decay Bc+χc0π+B_c^+\to\chi_{c0}\pi^+

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    A study of Bc+K+Kπ+B_c^+\to K^+K^-\pi^+ decays is performed for the first time using data corresponding to an integrated luminosity of 3.0 fb1\mathrm{fb}^{-1} collected by the LHCb experiment in pppp collisions at centre-of-mass energies of 77 and 88 TeV. Evidence for the decay Bc+χc0(K+K)π+B_c^+\to\chi_{c0}(\to K^+K^-)\pi^+ is reported with a significance of 4.0 standard deviations, resulting in the measurement of σ(Bc+)σ(B+)×B(Bc+χc0π+)\frac{\sigma(B_c^+)}{\sigma(B^+)}\times\mathcal{B}(B_c^+\to\chi_{c0}\pi^+) to be (9.83.0+3.4(stat)±0.8(syst))×106(9.8^{+3.4}_{-3.0}(\mathrm{stat})\pm 0.8(\mathrm{syst}))\times 10^{-6}. Here B\mathcal{B} denotes a branching fraction while σ(Bc+)\sigma(B_c^+) and σ(B+)\sigma(B^+) are the production cross-sections for Bc+B_c^+ and B+B^+ mesons. An indication of bˉc\bar b c weak annihilation is found for the region m(Kπ+)<1.834GeV ⁣/c2m(K^-\pi^+)<1.834\mathrm{\,Ge\kern -0.1em V\!/}c^2, with a significance of 2.4 standard deviations.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-2016-022.html, link to supplemental material inserted in the reference

    Author Correction: Comprehensive analysis of chromothripsis in 2,658 human cancers using whole-genome sequencing (Nature Genetics, (2020), 52, 3, (331-341), 10.1038/s41588-019-0576-7)

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    Correction to: Nature Genetics, published online 05 February 2020. In the published version of this paper, the members of the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium were listed in the Supplementary Information; however, these members should have been included in the main paper. The original Article has been corrected to include the members and affiliations of the PCAWG Consortium in the main paper; the corrections have been made to the HTML version of the Article but not the PDF version. Additional corrections to affiliations have been made to the PDF and HTML versions of the original Article for consistency of information between the PCAWG list and the main paper

    Measurement of the B0s →J/ψη lifetime

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    Using a data set corresponding to an integrated luminosity of 3 fb−1, collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV, the effective lifetime in the Bs0→J/ψη decay mode, τeff, is measured to be τeff=1.479±0.034 (stat)±0.011 (syst) ps. Assuming CP conservation, τeff corresponds to the lifetime of the light Bs0 mass eigenstate. This is the first measurement of the effective lifetime in this decay mode

    MYC-containing amplicons in acute myeloid leukemia: genomic structures, evolution, and transcriptional consequences.

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    Double minutes (dmin), homogeneously staining regions, and ring chromosomes are vehicles of gene amplification in cancer. The underlying mechanism leading to their formation as well as their structure and function in acute myeloid leukemia (AML) remain mysterious. We combined a range of high-resolution genomic methods to investigate the architecture and expression pattern of amplicons involving chromosome band 8q24 in 23 cases of AML (AML-amp). This revealed that different MYC-dmin architectures can coexist within the same leukemic cell population, indicating a step-wise evolution rather than a single event origin, such as through chromothripsis. This was supported also by the analysis of the chromothripsis criteria, that poorly matched the model in our samples. Furthermore, we found that dmin could evolve toward ring chromosomes stabilized by neocentromeres. Surprisingly, amplified genes (mainly PVT1) frequently participated in fusion transcripts lacking a corresponding DNA template. We also detected a significant overexpression of the circular RNA of PVT1 (circPVT1) in AML-amp cases versus AML with a normal karyotype. Our results show that 8q24 amplicons in AML are surprisingly plastic DNA structures with an unexpected association to novel fusion transcripts and circular RNAs

    Observation of B+c → D0K+ decays

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    Using proton-proton collision data corresponding to an integrated luminosity of 3.0 fb−1, recorded by the LHCb detector at center-of-mass energies of 7 and 8 TeV, the B+ c → D0K+ decay is observed with a statistical significance of 5.1 standard deviations. By normalizing to B+ → D¯ 0π+ decays, a measurement of the branching fraction multiplied by the production rates for B+ c relative to B+ mesons in the LHCb acceptance is obtained, R D 0 K = ( f c / f u ) × B ( B + c → D 0 K + ) = ( 9. 3 + 2.8 − 2.5 ± 0.6 ) × 10 − 7, where the first uncertainty is statistical and the second is systematic. This decay is expected to proceed predominantly through weak annihilation and penguin amplitudes, and is the first B+ c decay of this nature to be observed

    Measurement of the B_{s}^{0}→μ^{+}μ^{-} Branching Fraction and Effective Lifetime and Search for B^{0}→μ^{+}μ^{-} Decays.

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    A search for the rare decays B_{s}^{0}→μ^{+}μ^{-} and B^{0}→μ^{+}μ^{-} is performed at the LHCb experiment using data collected in pp collisions corresponding to a total integrated luminosity of 4.4  fb^{-1}. An excess of B_{s}^{0}→μ^{+}μ^{-} decays is observed with a significance of 7.8 standard deviations, representing the first observation of this decay in a single experiment. The branching fraction is measured to be B(B_{s}^{0}→μ^{+}μ^{-})=(3.0±0.6_{-0.2}^{+0.3})×10^{-9}, where the first uncertainty is statistical and the second systematic. The first measurement of the B_{s}^{0}→μ^{+}μ^{-} effective lifetime, τ(B_{s}^{0}→μ^{+}μ^{-})=2.04±0.44±0.05  ps, is reported. No significant excess of B^{0}→μ^{+}μ^{-} decays is found, and a 95% confidence level upper limit, B(B^{0}→μ^{+}μ^{-})<3.4×10^{-10}, is determined. All results are in agreement with the standard model expectations

    Pan-cancer analysis of whole genomes

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    Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

    Measurement of the CKM angle γ\gamma using B0DK0B^0 \rightarrow D K^{*0} with DKS0π+πD \rightarrow K^0_S \pi^+ \pi^- decays

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    A model-dependent amplitude analysis of the decay B0D(KS0π+π)K0B^0\rightarrow D(K^0_S\pi^+\pi^-) K^{*0} is performed using proton-proton collision data corresponding to an integrated luminosity of 3.0fb1^{-1}, recorded at s=7\sqrt{s}=7 and 8TeV8 TeV by the LHCb experiment. The CP violation observables x±x_{\pm} and y±y_{\pm}, sensitive to the CKM angle γ\gamma, are measured to be \begin{eqnarray*} x_- &=& -0.15 \pm 0.14 \pm 0.03 \pm 0.01, y_- &=& 0.25 \pm 0.15 \pm 0.06 \pm 0.01, x_+ &=& 0.05 \pm 0.24 \pm 0.04 \pm 0.01, y_+ &=& -0.65^{+0.24}_{-0.23} \pm 0.08 \pm 0.01, \end{eqnarray*} where the first uncertainties are statistical, the second systematic and the third arise from the uncertainty on the DKS0π+πD\rightarrow K^0_S \pi^+\pi^- amplitude model. These are the most precise measurements of these observables. They correspond to γ=(8022+21)\gamma=(80^{+21}_{-22})^{\circ} and rB0=0.39±0.13r_{B^0}=0.39\pm0.13, where rB0r_{B^0} is the magnitude of the ratio of the suppressed and favoured B0DK+πB^0\rightarrow D K^+ \pi^- decay amplitudes, in a KπK\pi mass region of ±50MeV\pm50 MeV around the K(892)0K^*(892)^0 mass and for an absolute value of the cosine of the K0K^{*0} decay angle larger than 0.40.4.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-2016-007.htm
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