41 research outputs found

    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

    Search for dark matter produced in association with a Higgs boson decaying to a pair of bottom quarks in proton-proton collisions at root s=13TeV

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    A search for dark matter produced in association with a Higgs boson decaying to a pair of bottom quarks is performed in proton-proton collisions at a center-of-mass energy of 13 TeV collected with the CMS detector at the LHC. The analyzed data sample corresponds to an integrated luminosity of 35.9 fb(-1). The signal is characterized by a large missing transverse momentum recoiling against a bottom quark-antiquark system that has a large Lorentz boost. The number of events observed in the data is consistent with the standard model background prediction. Results are interpreted in terms of limits both on parameters of the type-2 two-Higgs doublet model extended by an additional light pseudoscalar boson a (2HDM+a) and on parameters of a baryonic Z simplified model. The 2HDM+a model is tested experimentally for the first time. For the baryonic Z model, the presented results constitute the most stringent constraints to date.Peer reviewe

    A Deep Neural Network for Simultaneous Estimation of b Jet Energy and Resolution

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    We describe a method to obtain point and dispersion estimates for the energies of jets arising from b quarks produced in proton-proton collisions at an energy of s = 13 TeV at the CERN LHC. The algorithm is trained on a large sample of simulated b jets and validated on data recorded by the CMS detector in 2017 corresponding to an integrated luminosity of 41 fb - 1 . A multivariate regression algorithm based on a deep feed-forward neural network employs jet composition and shape information, and the properties of reconstructed secondary vertices associated with the jet. The results of the algorithm are used to improve the sensitivity of analyses that make use of b jets in the final state, such as the observation of Higgs boson decay to b b ¯

    Search for the production of W^{\pm} W^{\pm} W^{\mp} events at \sqrt{s} = 13 TeV

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    A search for the production of events containing three W bosons predicted by the standard model is reported. The search is based on a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the CMS experiment at the CERN LHC and corresponding to a total integrated luminosity of 35.9 fb^{-1}. The search is performed in final states with three leptons (electrons or muons), or with two same-charge leptons plus two jets. The observed (expected) significance of the signal for W^{\pm} W^{\pm} W^{\mp} production is 0.60 (1.78) standard deviations, and the ratio of the measured signal yield to that expected from the standard model is 0.34_{-0.34}^{+0.62}. Limits are placed on three anomalous quartic gauge couplings and on the production of massive axionlike particles

    Search for dark matter produced in association with a leptonically decaying Z boson in proton–proton collisions at s√=13TeV

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    A search for dark matter particles is performed using events with a Z boson candidate and large missing transverse momentum. The analysis is based on proton–proton collision data at a center-of-mass energy of 13TeV, collected by the CMS experiment at the LHC in 2016–2018, corresponding to an integrated luminosity of 137fb−1. The search uses the decay channels Z→ee and Z→μμ. No significant excess of events is observed over the background expected from the standard model. Limits are set on dark matter particle production in the context of simplified models with vector, axial-vector, scalar, and pseudoscalar mediators, as well as on a two-Higgs-doublet model with an additional pseudoscalar mediator. In addition, limits are provided for spin-dependent and spin-independent scattering cross sections and are compared to those from direct-detection experiments. The results are also interpreted in the context of models of invisible Higgs boson decays, unparticles, and large extra dimensions.SCOAP

    Measurements of pp → ZZ production cross sections and constraints on anomalous triple gauge couplings at √ = 13 TeV

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    © 2021 The CMS Collaboration. The production of Z boson pairs in proton–proton (pp) collisions, pp → (Z/∗)(Z/∗) → 2ℓ2ℓ′, where ℓ,ℓ′ = e or μ, is studied at a center-of-mass energy of 13 TeV with the CMS detector at the CERN LHC. The data sample corresponds to an integrated luminosity of 137fb−1, collected during 2016–2018. The ZZ production cross section, tot(pp → ZZ) = 17.4 ± 0.3 (stat) ± 0.5 (syst) ± 0.4 (Theo) ± 0.3 (lumi) pb, measured for events with two pairs of opposite-sign, same-flavor leptons produced in the mass region 60 < ℓ+ℓ− < 120 GeV is consistent with standard model predictions. Differential cross sections are also measured and agree with theoretical predictions. The invariant mass distribution of the four-lepton system is used to set limits on anomalous ZZZ and ZZ couplings.SCOAP

    Studies of B_{s2}^{*} (5840)⁰ and B_{s1} (5830)⁰ mesons including the observation of the B_{s2}^{*} (5840)⁰ → B⁰K_{s}^{0} decay in proton-proton collisions at √s = 8 TeV

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    Measurements of B_{s2}^{*} (5840)⁰ and B_{s1} (5840)⁰ mesons are performed using a data sample of proton-proton collisions corresponding to an integrated luminosity of 19.6 fb⁻¹, collected with the CMS detector at the LHC at a centre-of-mass energy of 8 TeV. The analysis studies P-wave B_{s}^{0} meson decays into B^{(*)}⁺K⁻ and B^{(*)}⁰K_{s}^{0}, where the B⁺ and B⁰ mesons are identified using the decays B⁺ → J/φK⁺ and B⁰ → J/φK* (892)⁰. The masses of the P-wave B_{s}^{0} meson states are measured and the natural width of the B_{*}^{s2} (5840)⁰ state is determined. The first measurement of the mass difference between the charged and neutral B* mesons is also presented. The B_{*}^{s2} (5840)⁰ decay to B⁰K_{s}^{0} is observed, together with a measurement of its branching fraction relative to the B_{s2}^{*} (5840)⁰ → B⁺K⁻ decay

    Search for vector-like quarks in events with two oppositely charged leptons and jets in proton-proton collisions at root s=13TeV

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    A search for the pair production of heavy vector-like partners T and B of the top and bottom quarks has been performed by the CMS experiment at the CERN LHC using proton–proton collisions at s√=13TeV. The data sample was collected in 2016 and corresponds to an integrated luminosity of 35.9fb−1. Final states studied for TT¯¯¯¯ production include those where one of the T quarks decays via T→tZ and the other via T→bW, tZ, or tH, where H is a Higgs boson. For the BB¯¯¯¯ case, final states include those where one of the B quarks decays via B→bZ and the other B→tW, bZ, or bH. Events with two oppositely charged electrons or muons, consistent with coming from the decay of a Z boson, and jets are investigated. The number of observed events is consistent with standard model background estimations. Lower limits at 95% confidence level are placed on the masses of the T and B quarks for a range of branching fractions. Assuming 100% branching fractions for T→tZ, and B→bZ, T and B quark mass values below 1280 and 1130GeV, respectively, are excluded
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