19 research outputs found

    An embedding technique to determine ττ backgrounds in proton-proton collision data

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    An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

    Performance of missing transverse momentum reconstruction in proton-proton collisions at root s=13 TeV using the CMS detector

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    The performance of missing transverse momentum ((p) over right arrow (miss)(T)) reconstruction algorithms for the CMS experiment is presented, using proton-proton collisions at a center-of-mass energy of 13 TeV, collected at the CERN LHC in 2016. The data sample corresponds to an integrated luminosity of 35.9 fb(-1). The results include measurements of the scale and resolution of (p) over right arrow (miss)(T), and detailed studies of events identified with anomalous (p) over right arrow (miss)(T). The performance is presented of a (p) over right arrow (miss)(T) reconstruction algorithm that mitigates the effects of multiple proton-proton interactions, using the "pileup per particle identification" method. The performance is shown of an algorithm used to estimate the compatibility of the reconstructed (p) over right arrow (miss)(T) with the hypothesis that it originates from resolution effects.Peer reviewe

    Prevalence, Type, and Molecular Spectrum of NF1 Mutations in Patients with Neurofibromatosis Type 1 and Congenital Heart Disease

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    The aim of this study was to assess the prevalence and type of congenital heart disease (CHD) and the associated mutation spectrum in a large series of patients with neurofibromatosis type 1 (NF1), and correlate the mutation type with the presence and subgroups of cardiac defects. The study cohort included 493 individuals with molecularly confirmed diagnosis of NF1 for whom cardiac evaluation data were available. CHD was reported in 62/493 (12.6%) patients. Among these patients, 23/62 (37.1%) had pulmonary valve stenosis/dysplasia, 20/62 (32.3%) had mitral valve anomalies, and 10/62 (16.1%) had septal defects. Other defects occurred as rare events. In this NF1 subcohort, three subjects carried a whole-gene deletion, while 59 were heterozygous for an intragenic mutation. A significantly increased prevalence of non-truncating intragenic mutations was either observed in individuals with CHD (22/59, 37.3%) or with pulmonary valve stenosis (13/20, 65.0%), when compared to individuals without CHD (89/420, 21.2%) (p = 0.038) or pulmonary valve stenosis (98/459, 21.4%) (p = 0.002). Similarly, patients with non-truncating NF1 mutations displayed two- and six-fold higher risk of developing CHD (odds ratio = 1.9713, 95% confidence interval (CI): 1.1162–3.4814, p = 0.0193) and pulmonary valve stenosis (odds ratio = 6.8411, 95% CI: 2.6574–17.6114, p = 0.0001), respectively. Noteworthy, all but one patient (19/20, 95.0%) with pulmonary valve stenosis, and 18/35 (51.4%) patients with other CHDs displayed Noonan syndrome (NS)-like features. Present data confirm the significant frequency of CHD in patients with NF1, and provide further evidence for a higher than expected prevalence of NF1 in-frame variants and NS-like characteristics in NF1 patients with CHD, particularly with pulmonary valve stenosis

    An embedding technique to determine ττ\tau\tau backgrounds in proton-proton collision data

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    An embedding technique is presented to estimate standard model ττ\tau\tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed ΌΌ\mu\mu events and replaced with simulated tau leptons with the same kinematic properties. In this way a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at s=\sqrt{s}= 13 TeV corresponding to an integrated luminosity of 41.5 fb−1^{-1}

    Constraints on anomalous HVV couplings from the production of Higgs bosons decaying to τ\tau lepton pairs

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    A study is presented of anomalous HVV interactions of the Higgs boson, including its CP properties. The study uses Higgs boson candidates produced mainly in vector boson fusion and gluon fusion that subsequently decay to a pair of τ\tau leptons. The data were recorded by the CMS experiment at the LHC in 2016 at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 35.9 fb−1^{-1}. A matrix element technique is employed for the analysis of anomalous interactions. The results are combined with those from the H→4ℓ\mathrm{H}\to 4\ell decay channel presented earlier, yielding the most stringent constraints on anomalous Higgs boson couplings to electroweak vector bosons expressed as effective cross-section fractions and phases: the CP-violating parameter fa3cos⁥(ϕa3)=(0.00±0.27)×10−3f_{a3}\cos(\phi_{a3})=(0.00 \pm 0.27 )\times10^{-3} and the CP-conserving parameters fa2cos⁥(ϕa2)=(0.08−0.21+1.04)×10−3f_{a2}\cos(\phi_{a2})=(0.08^{+1.04}_{-0.21})\times10^{-3}, fΛ1cos⁥(ϕΛ1)=(0.00−0.09+0.53)×10−3f_{\Lambda1}\cos(\phi_{\Lambda1})=(0.00^{+0.53}_{-0.09})\times10^{-3}, and fΛ1ZÎłcos⁥(ϕΛ1ZÎł)=(0.0−1.3+1.1)×10−3f_{\Lambda1}^{\mathrm{Z}\gamma}\cos(\phi_{\Lambda1}^{\mathrm{Z}\gamma})=(0.0^{+1.1}_{-1.3})\times10^{-3}. The current data set does not allow for precise constraints on CP properties in the gluon fusion process. The results are consistent with standard model expectations.A study is presented of anomalous HVV interactions of the Higgs boson, including its CP properties. The study uses Higgs boson candidates produced mainly in vector boson fusion and gluon fusion that subsequently decay to a pair of τ leptons. The data were recorded by the CMS experiment at the LHC in 2016 at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 35.9  fb-1. A matrix element technique is employed for the analysis of anomalous interactions. The results are combined with those from the H→4ℓ decay channel presented earlier, yielding the most stringent constraints on anomalous Higgs boson couplings to electroweak vector bosons expressed as effective cross section fractions and phases: the CP-violating parameter fa3cos(ϕa3)=(0.00±0.27)×10-3 and the CP-conserving parameters fa2cos(ϕa2)=(0.08-0.21+1.04)×10-3, fΛ1cos(ϕΛ1)=(0.00-0.09+0.53)×10-3, and fΛ1ZÎłcos(ϕΛ1ZÎł)=(0.0-1.3+1.1)×10-3. The current dataset does not allow for precise constraints on CP properties in the gluon fusion process. The results are consistent with standard model expectations.A study is presented of anomalous HVV interactions of the Higgs boson, including its CPCP properties. The study uses Higgs boson candidates produced mainly in vector boson fusion and gluon fusion that subsequently decay to a pair of τ\tau leptons. The data were recorded by the CMS experiment at the LHC in 2016 at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 35.9 fb−1^{-1}. A matrix element technique is employed for the analysis of anomalous interactions. The results are combined with those from the H →4ℓ\to 4\ell decay channel presented earlier, yielding the most stringent constraints on anomalous Higgs boson couplings to electroweak vector bosons expressed as effective cross section fractions and phases: the CPCP-violating parameter fa3cos⁥(ϕa3)f_{a3}\cos(\phi_{a3}) == (0.00±0.27)×10−3(0.00 \pm 0.27) \times 10^{-3} and the CPCP-conserving parameters fa2cos⁥(ϕa2)f_{a2}\cos(\phi_{a2}) == (0.08−0.21+1.04)×10−3(0.08 ^{+1.04}_{-0.21}) \times 10^{-3}, fΛ1cos⁥(ϕΛ1)f_{\Lambda1}\cos(\phi_{\Lambda1}) == (0.00−0.09+0.53)×10−3(0.00 ^{+0.53}_{-0.09}) \times 10^{-3}, and fΛ1ZÎłcos⁥(ϕΛ1ZÎł)f_{\Lambda1}^{\mathrm{Z}\gamma}\cos(\phi_{\Lambda1}^{\mathrm{Z}\gamma}) == (0.0−1.3+1.1)×10−3(0.0 ^{+1.1}_{-1.3}) \times 10^{-3}. The current dataset does not allow for precise constraints on CPCP properties in the gluon fusion process. The results are consistent with standard model expectations

    Measurement of electroweak production of a W boson in association with two jets in proton-proton collisions at s=\sqrt{s}= 13 TeV

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    A measurement is presented of electroweak (EW) production of a W boson in association with two jets in proton-proton collisions at s=\sqrt{s}= 13 TeV. The data sample was recorded by the CMS Collaboration at the LHC and corresponds to an integrated luminosity of 35.9 fb−1^{-1}. The measurement is performed for the â„“Îœ\ell\nujj final state (with â„“Îœ\ell\nu indicating a lepton-neutrino pair, and j representing the quarks produced in the hard interaction) in a kinematic region defined by invariant mass mjj>m_\mathrm{jj} > 120 GeV and transverse momenta pTj>p_\mathrm{T j} > 25 GeV. The cross section of the process is measured in the electron and muon channels yielding σEW(\sigma_\mathrm{EW}(Wjj)=)= 6.23±\pm0.12 (stat)±\pm 0.61 (syst) pb per channel, in agreement with leading-order standard model predictions. The additional hadronic activity of events in a signal-enriched region is studied, and the measurements are compared with predictions. The final state is also used to perform a search for anomalous trilinear gauge couplings. Limits on anomalous trilinear gauge couplings associated with dimension-six operators are given in the framework of an effective field theory. The corresponding 95% confidence level intervals are −-2.3 <cWWW/Λ2<< c_{\mathrm{WWW}}/\Lambda^2 < 2.5 TeV−2^{-2}, −-8.8 <cW/Λ2<< c_{\mathrm{W}}/\Lambda^2 < 16 TeV−2^{-2}, and −-45 <cB/Λ2<< c_{\mathrm{B}}/\Lambda^2 < 46 TeV−2^{-2}. These results are combined with the CMS EW Zjj analysis, yielding the most stringent limit to date on the cWWWc_{\mathrm{WWW}} coupling: −-1.8 <cWWW/Λ2<< c_{\mathrm{WWW}}/\Lambda^2 < 2.0 TeV−2^{-2}

    Search for supersymmetry in final states with photons and missing transverse momentum in proton-proton collisions at 13 TeV

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    Results are reported for a search for supersymmetry in final states with photons and missing transverse momentum in proton-proton collisions at the LHC. The data sample corresponds to an integrated luminosity of 35.9 fb−1^{-1} collected at a center-of-mass energy of 13 TeV using the CMS detector. The results are interpreted in the context of models of gauge-mediated supersymmetry breaking. Production cross section limits are set on gluino and squark pair production in this framework. Gluino masses below 1.86 TeV and squark masses below 1.59 TeV are excluded at 95% confidence level

    Search for W boson decays to three charged pions

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    For the first time, a search for the rare decay of the W boson to three charged pions has been performed. Proton-proton collision data recorded by the CMS experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 77.3 fb−1^{-1}, have been analyzed. No significant excess is observed above the background expectation. An upper limit of 1.01×\times10−6^{-6} is set at 95% confidence level on the branching fraction of the W boson to three charged pions. This provides a strong motivation for theoretical calculations of this branching fraction

    Search for a Wâ€Č boson decaying to a vector-like quark and a top or bottom quark in the all-jets final statech

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    A search for a heavy Wâ€Č resonance decaying to one B or T vector-like quark and a top or bottom quark, respectively, is presented. The search uses proton-proton collision data collected in 2016 with the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9 fb−1^{−1} at s=13 \sqrt{s}=13 TeV. Both decay channels result in a final state with a top quark, a Higgs boson, and a b quark, each produced with significant energy. The all-hadronic decays of both the Higgs boson and the top quark are considered. The final-state jets, some of which correspond to merged decay products of a boosted top quark and a Higgs boson, are selected using jet substructure techniques, which help to suppress standard model backgrounds. A Wâ€Č boson signal would appear as a narrow peak in the invariant mass distribution of these jets. No significant deviation in data with respect to the standard model background predictions is observed. Cross section upper limits on Wâ€Č boson production in the top quark, Higgs boson, and b quark decay mode are set as a function of the Wâ€Č mass, for several vector-like quark mass hypotheses. These are the first limits for Wâ€Č boson production in this decay channel, and cover a range of 0.01 to 0.43 pb in the Wâ€Č mass range between 1.5 and 4.0 TeV

    Performance of missing transverse momentum reconstruction in proton-proton collisions at s=\sqrt{s} = 13 TeV using the CMS detector

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