1,071 research outputs found

    Diboson production at the LHC

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    These proceedings present an overview of the diboson production cross-section measurements and constraints on anomalous triple-gauge boson couplings performed by the ATLAS and CMS collaborations using proton-proton collisions produced at a centre-of-mass energy of √ s = 8 and 13 TeV at LHC. Results for all combinations of W, Z and γ gauge bosons are presented with emphasis on the new WZ production cross sections measured by ATLAS at √ s = 13 TeV and WW production cross section measured by CMS at √ s = 13 TeV. New constraints on anomalous triple-gauge couplings have been set by both experiments at 8 TeV.Peer Reviewe

    Una nueva herramienta digital para el estudio de los hábitos de consumo de vino

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    Trabajo presentado en el XV Congreso Nacional de Investigación Enológica, celebrado en Murcia (España), del 23 al 26 de mayo de 2022Este trabajo nace de la necesidad de implementar nuevas metodologías que permitan cuantificar de forma objetiva y más precisa el consumo de vino, en relación con las herramientas más comunes basadas en las Encuestas de Frecuencia de Consumo de Alimentos (FFQ) que asignan 100 mL de forma fija para una copa/vaso de vino. El objetivo de este trabajo se ha centrado en el desarrollo de una herramienta digital de análisis de imagen, basada en inteligencia artificial que permita cuantificar la cantidad de vino tinto servido en una copa/vaso a partir de una simple fotografía tomada con un teléfono móvil. Para la construcción de la herramienta, se ha creado un banco de imágenes con 24.305 fotografías de estudio considerando una serie de variables que incluyen distintos tipos de copas/vasos y volúmenes de vino tinto, distintas condiciones de luz, fondo de fotografía, distancia del objeto y ángulo focal. A partir de este banco, se ha desarrollado un modelo basado en una red neuronal convolucional (CNN) de regresión que permite predecir el volumen de vino tinto a partir de una fotografía de la copa/vaso que contiene el vino. La aplicación del modelo ha demostrado un rendimiento satisfactorio con un error absoluto medio en la medida de volumen de vino inferior a 10 mL. A partir de este primer modelo, el siguiente paso es su optimización y validación incorporando al mismo fotografías que recojan situaciones reales de consumo de vino, en el contexto de la dieta y el estilo de vida de distintos grupos de la población. Esperamos que esta nueva herramienta basada en el análisis de imagen supondrá un soporte importante para la recogida de información sobre dieta y hábitos de consumo de vino mucho más objetiva que la recogida mediante encuestas. También esperamos aportar datos más precisos sobre los hábitos individuales de consumo de vino en España

    Open data provenance and reproducibility : a case study from publishing CMS open data

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    In this paper we present the latest CMS open data release published on the CERN Oopen Data portal. Samples of collision and simulated datasets were released together with detailed information about the data provenance. The associated data production chains cover the necessary computing environments, the configuration files and the computational procedures used in each data production step. We describe data curation techniques used to obtain and publish the data provenance information and we study the possibility of reproducing parts of the released data using the publicly available information. The present work demonstrates the usefulness of releasing selected samples of raw and primary data in order to fully ensure the completeness of information about the data production chain for the attention of general data scientists and other non-specialists interested in using particle physics data for education or research purposes.In this paper we present the latest CMS open data release published on the CERN Oopen Data portal. Samples of collision and simulated datasets were released together with detailed information about the data provenance. The associated data production chains cover the necessary computing environments, the configuration files and the computational procedures used in each data production step. We describe data curation techniques used to obtain and publish the data provenance information and we study the possibility of reproducing parts of the released data using the publicly available information. The present work demonstrates the usefulness of releasing selected samples of raw and primary data in order to fully ensure the completeness of information about the data production chain for the attention of general data scientists and other non-specialists interested in using particle physics data for education or research purposes.Peer reviewe

    Search for heavy resonances in the W/Z-tagged dijet mass spectrum in pp collisions at 7 TeV

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    A search has been made for massive resonances decaying into a quark and a vector boson, qW or qZ, or a pair of vector bosons, WW, WZ, or ZZ, where each vector boson decays to hadronic final states. This search is based on a data sample corresponding to an integrated luminosity of 5.0 fb^-^1 of proton-proton collisions collected in the CMS experiment at the LHC in 2011 at a center-of-mass energy of 7 TeV. For sufficiently heavy resonances the decay products of each vector boson are merged into a single jet, and the event effectively has a dijet topology. The background from QCD dijet events is reduced using recently developed techniques that resolve jet substructure. A 95% CL lower limit is set on the mass of excited quark resonances decaying into qW (qZ) at 2.38 TeV (2.15 TeV) and upper limits are set on the cross section for resonances decaying to qW, qZ, WW, WZ, or ZZ final states.Peer Reviewe

    Search for a non-standard-model Higgs boson decaying to a pair of new light bosons in four-muon final states

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    Results are reported from a search for non-standard-model Higgs boson decays to pairs of new light bosons, each of which decays into the μ+μ− final state. The new bosons may be produced either promptly or via a decay chain. The data set corresponds to an integrated luminosity of 5.3 fb−1 of proton–proton collisions at View the MathML source, recorded by the CMS experiment at the LHC in 2011. Such Higgs boson decays are predicted in several scenarios of new physics, including supersymmetric models with extended Higgs sectors or hidden valleys. Thus, the results of the search are relevant for establishing whether the new particle observed in Higgs boson searches at the LHC has the properties expected for a standard model Higgs boson. No excess of events is observed with respect to the yields expected from standard model processes. A model-independent upper limit of 0.86±0.06 fb on the product of the cross section times branching fraction times acceptance is obtained. The results, which are applicable to a broad spectrum of new physics scenarios, are compared with the predictions of two benchmark models as functions of a Higgs boson mass larger than 86 GeV/c2 and of a new light boson mass within the range 0.25–3.55 GeV/c2Peer Reviewe

    Measurement of the Production Cross Section for Pairs of Isolated Photons in pppp collisions at s=7\sqrt{s}=7 TeV

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    The integrated and differential cross sections for the production of pairs of isolated photons is measured in proton-proton collisions at a centre-of-mass energy of 7 TeV with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 36 inverse picobarns is analysed. A next-to-leading-order perturbative QCD calculation is compared to the measurements. A discrepancy is observed for regions of the phase space where the two photons have an azimuthal angle difference, Δ(ϕ)\Delta(\phi), less than approximately 2.8.Peer Reviewe

    Inclusive search for supersymmetry using the razor variables in pppp collisions at s=7\sqrt{s}=7 TeV

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    An inclusive search is presented for new heavy particle pairs produced in s\sqrt{s} = 7 TeV proton-proton collisions at the LHC using 4.7 +/- 0.1 inverse femtobarns of integrated luminosity. The selected events are analyzed in the 2D razor space of MR, an event-by-event indicator of the heavy particle mass scale, and R, a dimensionless variable related to the missing transverse energy. The third-generation sector is probed using the event heavy-flavor content. The search is sensitive to generic supersymmetry models with minimal assumptions about the superpartner decay chains. No excess is observed in the number of events beyond that predicted by the standard model. Exclusion limits are derived in the CMSSM framework as well as for simplified models. Within the CMSSM parameter space considered, gluino masses up to 800 GeV and squark masses up to 1.35 TeV are excluded at 95% confidence level depending on the model parameters. The direct production of pairs of stop or sbottom quarks is excluded for masses as high as 400 GeV.Peer Reviewe

    Search for signatures of extra dimensions in the diphoton mass spectrum at the Large Hadron Collider

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    A search for signatures of extra dimensions in the diphoton invariant-mass spectrum has been performed with the CMS detector at the LHC. No excess of events above the standard model expectation is observed using a data sample collected in proton-proton collisions at sqrt(s) = 7 TeV corresponding to an integrated luminosity of 2.2 inverse femtobarns. In the context of the large-extra-dimensions model, lower limits are set on the effective Planck scale in the range of 2.3-3.8 TeV at the 95% confidence level. These limits are the most restrictive bounds on virtual-graviton exchange to date. The most restrictive lower limits to date are also set on the mass of the first graviton excitation in the Randall-Sundrum model in the range of 0.86-1.84 TeV, for values of the associated coupling parameter between 0.01 and 0.10.Peer Reviewe

    Measurement of the charge asymmetry in top-quark pair production in proton-proton collisions at s=7\sqrt{s}=7 TeV

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    The difference in angular distributions between top quarks and antiquarks, commonly referred to as the charge asymmetry, is measured in pp collisions at the LHC with the CMS experiment. The data sample corresponds to an integrated luminosity of 1.09 inverse femtobarns at a centre-of-mass energy of 7 TeV. Top-quark pairs are selected in the final state with an electron or muon and four or more jets. At least one jet is identified as originating from b-quark hadronization. The charge asymmetry is measured in two variables, one based on the pseudorapidities (eta) of the top quarks and the other on their rapidities (y). The results A[C,eta] = -0.017 +/- 0.032 (stat.) + [+0.025/-0.036] (syst.) and A[C,y] = -0.013 +/- 0.028 (stat.) + [+0.029/-0.031] (syst.) are consistent within uncertainties with the standard-model predictions.Peer Reviewe
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