385 research outputs found

    Everything Matters: The ReproNim Perspective on Reproducible Neuroimaging

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    There has been a recent major upsurge in the concerns about reproducibility in many areas of science. Within the neuroimaging domain, one approach is to promote reproducibility is to target the re-executability of the publication. The information supporting such re-executability can enable the detailed examination of how an initial finding generalizes across changes in the processing approach, and sampled population, in a controlled scientific fashion. ReproNim: A Center for Reproducible Neuroimaging Computation is a recently funded initiative that seeks to facilitate the “last mile” implementations of core re-executability tools in order to reduce the accessibility barrier and increase adoption of standards and best practices at the neuroimaging research laboratory level. In this report, we summarize the overall approach and tools we have developed in this domain

    Performance of the local reconstruction algorithms for the CMS hadron calorimeter with Run 2 data

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    International audienceA description is presented of the algorithms used to reconstruct energy deposited in the CMS hadron calorimeter during Run 2 (2015-2018) of the LHC. During Run 2, the characteristic bunch-crossing spacing for proton-proton collisions was 25 ns, which resulted in overlapping signals from adjacent crossings. The energy corresponding to a particular bunch crossing of interest is estimated using the known pulse shapes of energy depositions in the calorimeter, which are measured as functions of both energy and time. A variety of algorithms were developed to mitigate the effects of adjacent bunch crossings on local energy reconstruction in the hadron calorimeter in Run 2, and their performance is compared

    Search for the lepton-flavor violating decay of the Higgs boson and additional Higgs bosons in the eμ\mu final state in proton-proton collisions at s\sqrt{s} = 13 TeV

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    A search for the lepton-flavor violating decay of the Higgs boson and potential additional Higgs bosons with a mass in the range 110-160 GeV to an e±μ^{\pm}\mu^{\mp} pair is presented. The search is performed with a proton-proton collision data set at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb1^{-1}. No excess is observed for the Higgs boson. The observed (expected) upper limit on the e±μ^{\pm}\mu^{\mp} branching fraction for it is determined to be 4.4 (4.7) ×\times 105^{-5} at 95% confidence level, the most stringent limit set thus far from direct searches. The largest excess of events over the expected background in the full mass range of the search is observed at an e±μ^{\pm}\mu^{\mp} invariant mass of approximately 146 GeV with a local (global) significance of 3.8 (2.8) standard deviations

    First measurement of the top quark pair production cross section in proton-proton collisions at s \sqrt{s} = 13.6 TeV

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    The first measurement of the top quark pair (tt \textrm{t}\overline{\textrm{t}} ) production cross section in proton-proton collisions at s \sqrt{s} = 13.6 TeV is presented. Data recorded with the CMS detector at the CERN LHC in Summer 2022, corresponding to an integrated luminosity of 1.21 fb1^{−1}, are analyzed. Events are selected with one or two charged leptons (electrons or muons) and additional jets. A maximum likelihood fit is performed in event categories defined by the number and flavors of the leptons, the number of jets, and the number of jets identified as originating from b quarks. An inclusive tt \textrm{t}\overline{\textrm{t}} production cross section of 881 ± 23 (stat + syst) ± 20 (lumi) pb is measured, in agreement with the standard model prediction of 92440+32 {924}_{-40}^{+32} pb.[graphic not available: see fulltext

    Search for new physics in multijet events with at least one photon and large missing transverse momentum in proton-proton collisions at 13 TeV

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    International audienceA search for new physics in final states consisting of at least one photon, multiple jets, and large missing transverse momentum is presented, using proton-proton collision events at a center-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 137 fb1^{-1}, recorded by the CMS experiment at the CERN LHC from 2016 to 2018. The events are divided into mutually exclusive bins characterized by the missing transverse momentum, the number of jets, the number of b-tagged jets, and jets consistent with the presence of hadronically decaying W, Z, or Higgs bosons. The observed data are found to be consistent with the prediction from standard model processes. The results are interpreted in the context of simplified models of pair production of supersymmetric particles via strong and electroweak interactions. Depending on the details of the signal models, gluinos and squarks of masses up to 2.35 and 1.43 TeV, respectively, and electroweakinos of masses up to 1.23 TeV are excluded at 95% confidence level

    Search for a high-mass dimuon resonance produced in association with b quark jets at s\sqrt{s}=13 TeV

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    International audienceA search for high-mass dimuon resonance production in association with one or more b quark jets is presented. The study uses proton-proton collision data collected with the CMS detector at the LHC corresponding to an integrated luminosity of 138 fb1^{-1} at a center-of-mass energy of 13 TeV. Model-independent limits are derived on the number of signal events with exactly one or more than one b quark jet. Results are also interpreted in a lepton-flavor-universal model with Z' boson couplings to a bb quark pair (gbg_\mathrm{b}), an sb quark pair (gbδbsg_\mathrm{b}\delta_\mathrm{bs}), and any same-flavor charged lepton (gg_\ell) or neutrino pair (gνg_\nu), with gν=g\left|g_{\nu}\right|=\left|g_\ell\right|. For a Z' boson with a mass mZm_{\mathrm{Z}'} = 350 GeV (2 TeV) and δbs<\left|\delta_\mathrm{bs}\right| \lt 0.25, the majority of the parameter space with 0.0057 <g<\lt \left|g_\ell\right| \lt 0.35 (0.25 <g<\lt \left|g_\ell\right| \lt 0.43) and 0.0079 <gb<\lt \left|g_\mathrm{b}\right| \lt 0.46 (0.34 <gb<\lt \left|g_\mathrm{b}\right| \lt 0.57) is excluded at 95% confidence level. Finally, constraints are set on a Z' model with parameters consistent with low-energy b \to s\ell\ell measurements. In this scenario, most of the allowed parameter space is excluded for a Z' boson with 350 <mZ<\lt m_{\mathrm{Z}'}\lt 500 GeV, while the constraints are less stringent for higher mZm_{\mathrm{Z}'} hypotheses. This is the first dedicated search at the LHC for a high-mass dimuon resonance produced in association with multiple b quark jets, and the constraints obtained on models with this signature are the most stringent to date

    Observation of the rare decay of the η\eta meson to four muons

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    A search for the rare η\eta\toμ+μμ+μ\mu^+\mu^-\mu^+\mu^- double-Dalitz decay is performed using a sample of proton-proton collisions, collected by the CMS experiment at the CERN LHC with high-rate muon triggers in 2017-2018 and corresponding to an integrated luminosity of 101 fb1^{-1}. A signal having a statistical significance well in excess of 5 standard deviations is observed. Using the \emm decay as normalization, the branching fraction B(\mathcal{B}(ημ+μμ+μ) \to \mu^+\mu^-\mu^+\mu^-) = ( 5.0 ±\pm 0.8 (stat) ±\pm 0.7 (syst) ±\pm 0.7 B2μ\mathcal{B}_{2\mu} ) ×\times 109^{-9} is measured, where the last term is the uncertainty in the normalization channel branching fraction. This is the first measurement of this branching fraction and is found to be in agreement with theoretical predictions
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