7,281 research outputs found
Measurement of associated W+ charm production in pp collisions at √s=7 TeV
No full textOpen Access, Copyright CERN, for the benefit of the CMS Collaboration.Measurements are presented of the associated production of a W boson and a charm-quark jet (W + c) in pp collisions at a center-of-mass energy of 7 TeV. The analysis is conducted with a data sample corresponding to a total integrated luminosity of 5 fb−1, collected by the CMS detector at the LHC. W boson candidates are identified by their decay into a charged lepton (muon or electron) and a neutrino. The W + c measurements are performed for charm-quark jets in the kinematic region p jet T > 25 GeV, |ηjet| 25 GeV) and σ(pp → W + c + X)× B (W → ℓν) = 84.1 ± 2.0 (stat.) ± 4.9 (syst.) pb ( p ℓ T > 35 GeV), and the cross section ratios σ(pp → W+ + c ¯ + X)/σ(pp → W− + c + X) = 0.954 ± 0.025 (stat.) ± 0.004 (syst.) ( p ℓ T > 25 GeV) and σ(pp → W+ + c ¯ + X)/σ(pp → W− + c + X) = 0.938 ± 0.019 (stat.) ± 0.006 (syst.) ( p ℓ T > 35 GeV). Cross sections and cross section ratios are also measured differentially with respect to the absolute value of the pseudorapidity of the lepton from the W-boson decay. These are the first measurements from the LHC directly sensitive to the strange quark and antiquark content of the proton. Results are compared with theoretical predictions and are consistent with the predictions based on global fits of parton distribution functions
Measurement of associated W plus charm production in pp collisions at √s=7 TeV
No full textIndividuals have received support from the Marie-Curie programme and the Euro- pean Research Council and EPLANET (European Union); the Leventis Foundation; the A.P. Sloan Foundation; the Alexander von Humboldt Foundation; the Belgian Federal Science Policy Office; the Fonds pour la Formation à la Recherche dans l’Industrie et dans l’Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the Ministry of Education, Youth and Sports (MEYS) of Czech Republic; the Council of Science and Industrial Research, India; the Compagnia di San Paolo (Torino); the HOMING PLUS programme of Foundation for Polish Science, cofinanced by EU, Regional Development Fund; and the Thalis and Aristeia programmes cofinanced by EU-ESF and the Greek NSRF.Chatrchyan, S., Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Bergauer, T., Dragicevic, M., Erö, J., Fabjan, C., Friedl, M., Frühwirth, R., Ghete, V.M., Hörmann, N., Hrubec, J., Jeitler, M., Kiesenhofer, W., Knünz, V., Krammer, M., Krätschmer, I., Liko, D., Mikulec, I., Rabady, D., Rahbaran, B., Rohringer, C., Rohringer, H., Schöfbeck, R., Strauss, J., Taurok, A., Treberer-Treberspurg, W., Waltenberger, W., Wulz, C.-E., Mossolov, V., Shumeiko, N., Suarez Gonzalez, J., Alderweireldt, S., Bansal, M., Bansal, S., Cornelis, T., De Wolf, E.A., Janssen, X., Knutsson, A., Luyckx, S., Mucibello, L., Ochesanu, S., Roland, B., Rougny, R., Staykova, Z., Van Haevermaet, H., Van Mechelen, P., Van Remortel, N., Van Spilbeeck, A., Blekman, F., Blyweert, S., D'Hondt, J., Kalogeropoulos, A., Keaveney, J., Maes, M., Olbrechts, A., Tavernier, S., Van Doninck, W., Van Mulders, P., Van Onsem, G.P., Villella, I., Caillol, C., Clerbaux, B., De Lentdecker, G., Favart, L., Gay, A.P.R., Hreus, T., Léonard, A., Marage, P.E., Mohammadi, A., Perniè, L., Reis, T., Seva, T., Thomas, L., Vander Velde, C., Vanlaer, P., Wang, J., Adler, V., Beernaert, K., Benucci, L., Cimmino, A., Costantini, S., Dildick, S., Garcia, G., Klein, B., Lellouch, J., Marinov, A., McCartin, J., Ocampo Rios, A.A., Ryckbosch, D., Sigamani, M., Strobbe, N., Thyssen, F., Tytgat, M., Walsh, S., Yazgan, E., Zaganidis, N
Search for the standard model Higgs boson produced in association with W and Z bosons in pp collisions at √s=7 TeV
No full textChatrchyan, S., Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Aguilo, E., Bergauer, T., Dragicevic, M., Erö, J., Fabjan, C., Friedl, M., Frühwirth, R., Ghete, V.M., Hammer, J., Hörmann, N., Hrubec, J., Jeitler, M., Kiesenhofer, W., Knünz, V., Krammer, M., Liko, D., Mikulec, I., Pernicka, M., Rahbaran, B., Rohringer, C., Rohringer, H., Schöfbeck, R., Strauss, J., Taurok, A., Waltenberger, W., Walzel, G., Widl, E., Wulz, C.-E., Mossolov, V., Shumeiko, N., Suarez Gonzalez, J., Bansal, S., Cornelis, T., De Wolf, E.A., Janssen, X., Luyckx, S., Mucibello, L., Ochesanu, S., Roland, B., Rougny, R., Selvaggi, M., Staykova, Z., Van Haevermaet, H., Van Mechelen, P., Van Remortel, N., Van Spilbeeck, A., Blekman, F., Blyweert, S., D'Hondt, J., Gonzalez Suarez, R., Kalogeropoulos, A., Maes, M., Olbrechts, A., Van Doninck, W., Van Mulders, P., Van Onsem, G.P., Villella, I., Clerbaux, B., De Lentdecker, G., Dero, V., Gay, A.P.R., Hreus, T., Léonard, A., Marage, P.E., Reis, T., Thomas, L., Vander Velde, C., Vanlaer, P., Wang, J., Adler, V., Beernaert, K., Cimmino, A., Costantini, S., Garcia, G., Grunewald, M., Klein, B., Lellouch, J., Marinov, A., McCartin, J., Ocampo Rios, A.A., Ryckbosch, D., Strobbe, N., Thyssen, F., Tytgat, M., Verwilligen, P., Walsh, S., Yazgan, E., Zaganidis, N., Basegmez, S., Bruno, G., Castello, R., Ceard, L., Delaere, C., Du Pree, T., Favart, D
Measurement of Higgs boson production and properties in the WW decay channel with leptonic final states
No full textA search for the standard model Higgs boson decaying to a W-boson pair at the LHC is reported. The event sample corresponds to an integrated luminosity of 4.9 fb−1 and 19.4 fb−1 collected with the CMS detector in pp collisions at s√ = 7 and 8 TeV, respectively. The Higgs boson candidates are selected in events with two or three charged leptons. An excess of events above background is observed, consistent with the expectation from the standard model Higgs boson with a mass of around 125 GeV. The probability to observe an excess equal or larger than the one seen, under the background-only hypothesis, corresponds to a significance of 4.3 standard deviations for m H = 125.6 GeV. The observed signal cross section times the branching fraction to WW for m H = 125.6 GeV is 0.72+0.20−0.18 times the standard model expectation. The spin-parity J P = 0+ hypothesis is favored against a narrow resonance with J P = 2+ or J P = 0− that decays to a W-boson pair. This result provides strong evidence for a Higgs-like boson decaying to a W-boson pair
Verantwortlicher Umgang mit ICDs. Stellungnahme der Deutschen Gesellschaft für Kardiologie und ihrer Schwester-Gesellschaften
No full textResponsible handling of ICDs Statement of the German Society of Cardiology and sister societies Abstract An increasing number of patients receive small implantable cardioverter/defibrillators (ICDs) embedded under their skin so as to prevent potentially life-threatening cardiac arrhythmias. As beneficial as these devices may be, they can also trigger problems, particularly when patients approach the end of life independent of their concomitant heart disease. In such cases, often many years after the initial implantation, ICDs may burden patients by unwanted shocks and by prolonging the process of dying. Fortunately, these problems can be eliminated by an ICD deactivation from outside, based on the patient’s (presumed) consent. Treating physicians, however, must be well acquainted with both the technical feasibility and equipment as well as the legal and ethical permissibility of such deactivations. Moreover, it is within the physicians’ responsibility to inform patients about these problems and their possible handling by an ICD directive in the context of advance care planning. The following report provides a systematic analysis of the aforementioned aspects as well as practical recommendations
A vertex reconstruction toolkit and interface to generic objects (VERTIGO)
No full textA proposal is made for the design and implementation of a detector-independent Vertex Reconstruction Toolkit (VERTIGO). It aims at re-using existing state-of-the-art algorithms for geometric vertex finding and fitting by both linear and robust estimation methods; kinematic constraints will also be included for the benefit of complex multi-vertex topologies. The design is based on modern object-oriented techniques. A core (RAVE) is surrounded by a shell of interfaces and a set of analysis & debugging tools. The implementation follows an open source approach and is easily adaptable to future standards
Measurement of the W+W- cross section in pp collisions at root s=8 TeV and limits on anomalous gauge couplings
No full textA measurement of the W boson pair production cross section in proton-proton collisions at root s = 8TeV is presented. The data collected with the CMS detector at the LHC correspond to an integrated luminosity of 19.4 fb(-1). The W+W- candidates are selected from events with two charged leptons, electrons or muons, and large missing transverse energy. The measured W+W- cross section is 60.1 +/- 0.9 (stat) +/- 3.2 (exp) +/- 3.1 (theo) +/- 1.6 (lumi) pb = 60.1 +/- 4.8 pb, consistent with the standard model prediction. The W+W- cross sections are also measured in two different fiducial phase space regions. The normalized differential cross section is measured as a function of kinematic variables of the final-state charged leptons and compared with several perturbative QCD predictions. Limits on anomalous gauge couplings associated with dimension-six operators are also given in the framework of an effective field theory. The corresponding 95 % confidence level intervals are -5.7 < c(WWW)/Lambda(2) < 5.9TeV(-2), -11.4 < c(W)/Lambda(2) < 5.4TeV(-2), -29.2 < c(B)/Lambda(2) < 23.9 TeV-2, in the HISZ basis
Measurement of the W boson helicity fractions in the decays of top quark pairs to lepton plus jets final states produced in pp collisions at root s=8 TeV
No full textThe W boson helicity fractions from top quark decays in t (t) over bar events are measured using data from proton-proton collisions at a centre-of-mass energy of 8 TeV. The data were collected in 2012 with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.8 fb(-1). Events are reconstructed with either one muon or one electron, along with four jets in the final state, with two of the jets being identified as originating from b quarks. The measured helicity fractions from both channels are combined, yielding F-0 = 0.681 +/- 0.012 (stat) +/- 0.023 (syst), F-L = 0.323 +/- 0.008 (stat) +/- 0.014 (syst), and F-R = -0.004 +/- 0.005 (stat) +/- 0.014 (syst) for the longitudinal, left-, and right-handed components of the helicity, respectively. These measurements of the W boson helicity fractions are the most accurate to date and they agree with the predictions from the standard model. (C) 2016 The Author. Published by Elsevier B.V
Search for heavy gauge W ' bosons in events with an energetic lepton and large missing transverse momentum at root s=13TeV
No full textA search is presented for W' bosons in events with an electron or muon and large missing transverse momentum, using proton-proton collision data at root s = 13 TeV collected with the CMS detector in 2015 and corresponding to an integrated luminosity of 2.3 fb(-1). No evidence of an excess of events relative to the standard model expectations is observed. For a W' boson described by the sequential standard model, upper limits at 95% confidence level are set on the product of the production cross section and branching fraction and lower limits are established on the new boson mass. Masses below 4.1 TeV are excluded combining electron and muon decay channels, significantly improving upon the results obtained with the 8 TeV data. Exclusion limits at 95% confidence level on the product of the W' production cross section and branching fraction are also derived in combination with the 8 TeV data. Finally, exclusion limits are set for the production of generic W' bosons decaying into this final state using a model-independent approach. (C) 2017 The Author. Published by Elsevier B.V
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