19 research outputs found

    A multiplexing architecture for mixed-signal CMOS fuzzy controllers

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    Limits to precision impose limits to the complexity of analog circuits, hence fuzzy analog controllers are usually oriented to fast low-power systems with low-medium complexity. This paper presents a strategy to preserve most of the advantages of an analog implementation, while allowing a marked increment in system complexity.The works in this papaer has been partially funded by the spanish C.I.C.Y.T. under contract TIC96-1392-C02-02 (SIVA

    Search for pair-produced resonances decaying to quark pairs in proton-proton collisions at root s=13 TeV

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    A general search for the pair production of resonances, each decaying to two quarks, is reported. The search is conducted separately for heavier resonances (masses above 400 GeV), where each of the four final-state quarks generates a hadronic jet resulting in a four-jet signature, and for lighter resonances (masses between 80 and 400 GeV), where the pair of quarks from each resonance is collimated and reconstructed as a single jet resulting in a two-jet signature. In addition, a b-tagged selection is applied to target resonances with a bottom quark in the final state. The analysis uses data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 35.9 fb(-1), from proton-proton collisions at a center-of-mass energy of 13 TeV. The mass spectra are analyzed for the presence of new resonances, and are found to be consistent with standard model expectations. The results are interpreted in the framework of R-parity-violating supersymmetry assuming the pair production of scalar top quarks decaying via the hadronic coupling lambda ''(312) or lambda ''(323) and upper limits on the cross section as a function of the top squark mass are set. These results probe a wider range of masses than previously explored at the LHC, and extend the top squark mass limits in the (t) over tilde -> qq' scenario.Peer reviewe

    Measurement of the cross section for tt \mathrm{t}\overline{\mathrm{t}} production with additional jets and b jets in pp collisions at s \sqrt{s} = 13 TeV

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    Measurements of the cross section for the production of top quark pairs in association with a pair of jets from bottom quarks (σttbb) \left({\sigma}_{\mathrm{t}\overline{\mathrm{t}}\mathrm{b}\overline{\mathrm{b}}}\right) and in association with a pair of jets from quarks of any flavor or gluons (σttjj) \left({\sigma}_{\mathrm{t}\overline{\mathrm{t}}\mathrm{jj}}\right) and their ratio are presented. The data were collected in proton-proton collisions at a center-of-mass energy of 13 TeV by the CMS experiment at the LHC in 2016 and correspond to an integrated luminosity of 35.9 fb−1. The measurements are performed in a fiducial phase space and extrapolated to the full phase space, separately for the dilepton and lepton+jets channels, where lepton corresponds to either an electron or a muon. The results of the measurements in the fiducial phase space for the dilepton and lepton+jets channels, respectively, are σttjj {\sigma}_{\mathrm{t}\overline{\mathrm{t}}\mathrm{jj}} = 2.36±0.02 (stat)±0.20 (syst) pb and 31.0±0.2 (stat)±2.9 (syst) pb, and for the cross section ratio 0.017 ± 0.001 (stat) ± 0.001 (syst) and 0.020 ± 0.001 (stat) ± 0.001 (syst). The values of σttbb {\sigma}_{\mathrm{t}\overline{\mathrm{t}}\mathrm{b}\overline{\mathrm{b}}} are determined from the product of the σttjj {\sigma}_{\mathrm{t}\overline{\mathrm{t}}\mathrm{jj}} and the cross section ratio, obtaining, respectively, 0.040±0.002 (stat)±0.005 (syst) pb and 0.62±0.03 (stat)±0.07 (syst) pb. These measurements are the most precise to date and are consistent, within the uncertainties, with the standard model expectations obtained using a matrix element calculation at next-to-leading order in quantum chromodynamics matched to a parton shower

    Observation of the Λb0→J/ψΛφ decay in proton-proton collisions at s=13TeV

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    The observation of the Λb0→J/ψΛφ decay is reported using proton-proton collision data collected at s=13TeV by the CMS experiment at the LHC in 2018, corresponding to an integrated luminosity of 60fb−1. The ratio of the branching fractions B(Λb0→J/ψΛφ)/B(Λb0→ψ(2S)Λ) is measured to be (8.26±0.90(stat)±0.68(syst)±0.11(B))×10−2, where the first uncertainty is statistical, the second is systematic, and the last uncertainty reflects the uncertainties in the world-average branching fractions of φ and ψ(2S) decays to the reconstructed final states

    A search for the standard model Higgs boson decaying to charm quarks

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    A direct search for the standard model Higgs boson, H, produced in association with a vector boson, V (W or Z), and decaying to a charm quark pair is presented. The search uses a data set of proton-proton collisions corresponding to an integrated luminosity of 35.9 fb−1, collected by the CMS experiment at the LHC in 2016, at a centre-of-mass energy of 13 TeV. The search is carried out in mutually exclusive channels targeting specific decays of the vector bosons: W → lν, Z → ll, and Z → νν, where l is an electron or a muon. To fully exploit the topology of the H boson decay, two strategies are followed. In the first one, targeting lower vector boson transverse momentum, the H boson candidate is reconstructed via two resolved jets arising from the two charm quarks from the H boson decay. A second strategy identifies the case where the two charm quark jets from the H boson decay merge to form a single jet, which generally only occurs when the vector boson has higher transverse momentum. Both strategies make use of novel methods for charm jet identification, while jet substructure techniques are also exploited to suppress the background in the merged-jet topology. The two analyses are combined to yield a 95% confidence level observed (expected) upper limit on the cross section σ(VH)B(Hcc) \sigma \left(\mathrm{VH}\right)\mathrm{\mathcal{B}}\left(\mathrm{H}\to \mathrm{c}\overline{\mathrm{c}}\right) of 4.5 (2.40.7+1.0) \left({2.4}_{-0.7}^{+1.0}\right) pb, corresponding to 70 (37) times the standard model prediction

    Measurement of ttˉ\hbox {t}{\bar{\hbox {t}}} normalised multi-differential cross sections in pp{\text {p}}{\text {p}} collisions at s=13TeV\sqrt{s}=13\,{\text {TeV}} , and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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    Normalised multi-differential cross sections for top quark pair (ttˉ\hbox {t}{\bar{\hbox {t}}}) production are measured in proton-proton collisions at a centre-of-mass energy of 13TeV\,{\text {TeV}} using events containing two oppositely charged leptons. The analysed data were recorded with the CMS detector in 2016 and correspond to an integrated luminosity of 35.9fb135.9{\,{\text {fb}}^{-1}} . The double-differential ttˉ\hbox {t}{\bar{\hbox {t}}} cross section is measured as a function of the kinematic properties of the top quark and of the ttˉ\hbox {t}{\bar{\hbox {t}}} system at parton level in the full phase space. A triple-differential measurement is performed as a function of the invariant mass and rapidity of the ttˉ\hbox {t}{\bar{\hbox {t}}} system and the multiplicity of additional jets at particle level. The data are compared to predictions of Monte Carlo event generators that complement next-to-leading-order (NLO) quantum chromodynamics (QCD) calculations with parton showers. Together with a fixed-order NLO QCD calculation, the triple-differential measurement is used to extract values of the strong coupling strength αS\alpha _{S} and the top quark pole mass (mtpolem_{{\text {t}}}^{{\text {pole}}}) using several sets of parton distribution functions (PDFs). The measurement of mtpolem_{{\text {t}}}^{{\text {pole}}} exploits the sensitivity of the ttˉ\hbox {t}{\bar{\hbox {t}}} invariant mass distribution to mtpolem_{{\text {t}}}^{{\text {pole}}} near the production threshold. Furthermore, a simultaneous fit of the PDFs, αS\alpha _{S}, and mtpolem_{{\text {t}}}^{{\text {pole}}} is performed at NLO, demonstrating that the new data have significant impact on the gluon PDF, and at the same time allow an accurate determination of αS\alpha _{S} and mtpolem_{{\text {t}}}^{{\text {pole}}}. The values αS(mZ)=0.11350.0017+0.0021\alpha _{S}(m_{{\text {Z}}}) = 0.1135{}^{+0.0021}_{-0.0017} and mtpole=170.5±0.8GeVm_{{\text {t}}}^{{\text {pole}}} = 170.5 \pm 0.8 \,{\text {GeV}} are extracted, which account for experimental and theoretical uncertainties, the latter being estimated from NLO scale variations. Possible effects from Coulomb and soft-gluon resummation near the ttˉ\hbox {t}{\bar{\hbox {t}}} production threshold are neglected in these parameter extractions. A rough estimate of these effects indicates an expected correction of mtpolem_{{\text {t}}}^{{\text {pole}}} of the order of +1GeV+1 \,{\text {GeV}} , which can be regarded as additional theoretical uncertainty in the current mtpolem_{{\text {t}}}^{{\text {pole}}} extraction

    Constraints on the {\ensuremath{\chi}}_{c1} versus {\ensuremath{\chi}}_{c2} Polarizations in Proton-Proton Collisions at s=8  TeV\sqrt{s}=8\text{ }\text{ }\mathrm{TeV}

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    Search for Supersymmetry with a Compressed Mass Spectrum in Events with a Soft \ensuremath{\tau} Lepton, a Highly Energetic Jet, and Large Missing Transverse Momentum in Proton-Proton Collisions at s=13  TeV\sqrt{s}=13\text{ }\text{ }\mathrm{TeV}

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    Search for low mass vector resonances decaying into quark-antiquark pairs in proton-proton collisions at s=13  TeV\sqrt{s}=13\text{ }\text{ }\mathrm{TeV}

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