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Search for W′ → tb in proton-proton collisions at s = 8 $$ \sqrt{s}=8 $$ TeV
Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Asilar, E.,Bergauer, T.,Brandstetter, J.,Brondolin, E.,Dragicevic, M.,Erö,, J.,Flechl, M.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hartl, C. Institute of Physics Pub 2016 The journal of high energy physics Vol.2016 No.2
<P>A search is performed for the production of a massive W' boson decaying to a top and a bottom quark. The data analysed correspond to an integrated luminosity of 19.71 fb(-1) collected with the CMS detector at the LHC in proton-proton collisions at root s = 8 TeV. The hadronic decay products of the top quark with high Lorentz boost from the W' boson decay are detected as a single top flavoured jet. The use of jet substructure algorithms allows the top quark jet to be distinguished from standard model QCD background. Limits on the production cross section of a right-handed W' boson are obtained, together with constraints on the left-handed and right-handed couplings of the W' boson to quarks. The production of a right-handed W' boson with a mass below 2.02 TeV decaying to a hadronic final state is excluded at 95% confidence level. This mass limit increases to 2.15 TeV when both hadronic and leptonic decays are considered, and is the most stringent lower mass limit to date in the tb decay mode.</P>
Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Ambrogi, F.,Asilar, E.,Bergauer, T.,Brandstetter, J.,Brondolin, E.,Dragicevic, M.,Erö,, J.,Flechl, M.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Grossmann, J. Institute of Physics Pub 2017 The journal of high energy physics Vol.2017 No.8
<P>Searches are presented for heavy gauge bosons decaying into a top and a bottom quark in data collected by the CMS experiment at root s = 13TeV that correspond to an integrated luminosity of 2.2 and 2.6 fb 1 in the leptonic and hadronic analyses, respectively. Two final states are analyzed, one containing a single electron, or muon, and missing transverse momentum, and the other containing multiple jets and no electrons or muons. No evidence is found for a right-handed W' boson (W'(R)) and the combined analyses exclude at 95% confidence level W'(R) with masses below 2.4TeV if M-W'R >> M-vR (mass of the right-handed neutrino), and below 2.6TeV if M-W'R < M-vR. The results provide the most stringent limits for right-handed W' bosons in the top and bottom quark decay channel.</P>
Search for W′ → tb decays in the lepton + jets final state in pp collisions at $ \sqrt{s} $ = 8 TeV
Chatrchyan, S.,Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hartl, C.,Hö,rmann, N.,Hrubec, J Springer-Verlag 2014 Journal of high energy physics Vol.2014 No.5
<P>Results are presented from a search for the production of a heavy gauge boson W' decaying into a top and a bottom quark, using a data set collected by the CMS experiment at root s = 8 TeV and corresponding to an integrated luminosity of 19.5 fb(-1). Various models of W'-boson production are studied by allowing for an arbitrary combination of left-and right-handed couplings. The analysis is based on the detection of events with a lepton (e, mu), jets, and missing transverse energy in the final state. No evidence for W'-boson production is found and 95% confidence level upper limits on the production cross section times branching fraction are obtained. For W' bosons with purely right-handed couplings, and for those with left-handed couplings assuming no interference effects, the observed 95% confidence level limit is M(W') > 2.05TeV. For W' bosons with purely left-handed couplings, including interference effects, the observed 95% confidence level limit is M(W') > 1.84 TeV. The results presented in this paper are the most stringent limits published to date.</P>
Chatrchyan, S.,Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hö,rmann, N.,Hrubec, J.,Jeitler, Springer-Verlag 2013 The European physical journal. C, Particles and fi Vol.73 No.10
<P>A measurement of W+W- production in pp collisions at is presented. The data were collected with the CMS detector at the LHC, and correspond to an integrated luminosity of 4.92 +/- 0.11 fb(-1). The W+W- candidates consist of two oppositely charged leptons, electrons or muons, accompanied by large missing transverse energy. The W+W- production cross section is measured to be 52.4 +/- 2.0 (stat.)+/- 4.5 (syst.)+/- 1.2 (lum.) pb. This measurement is consistent with the standard model prediction of 47.0 +/- 2.0 pb at next-to-leading order. Stringent limits on the WW gamma and WWZ anomalous triple gauge-boson couplings are set.</P>
Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Ambrogi, F.,Asilar, E.,Bergauer, T.,Brandstetter, J.,Brondolin, E.,Dragicevic, M.,Erö,, J.,Escalante Del Valle, A.,Flechl, M.,Friedl, M.,Frü,hwirth, R.,Gh Institute of Physics Pub 2018 The journal of high energy physics Vol.2018 No.5
<P>A search for a heavy right-handed W boson (W-R) decaying to a heavy right-handed neutrino and a charged lepton in events with two same-flavor leptons (e or mu) and two jets, is presented. The analysis is based on proton-proton collision data, collected by the CMS Collaboration at the LHC in 2016 and corresponding to an integrated luminosity of 35.9 fb(-1). No significant excess above the standard model expectation is seen in the invariant mass distribution of the dilepton plus dijet system. Assuming that couplings are identical to those of the standard model, and that only one heavy neutrino flavor N-R contributes significantly to the W-R decay width, the region in the two-dimensional (m(WR), m(NR)) mass plane excluded at 95% confidence level extends to approximately m(WR) = 4 : 4TeV and covers a large range of right-handed neutrino masses below the W-R boson mass. This analysis provides the most stringent limits on the W-R mass to date.</P>
Search for leptonic decays of W′ bosons in pp collisions at $ \sqrt {s} = {7} $ TeV
Chatrchyan, S.,Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hammer, J.,Hö,rmann, N.,Hrubec, Springer-Verlag 2012 Journal of high energy physics Vol.2012 No.8
<P>A search for a new heavy gauge boson W' decaying to an electron or muon, plus a low mass neutrino, is presented. This study uses data corresponding to an integrated luminosity of 5.0 fb(-1), collected using the CMS detector in pp collisions at a centre-of-mass energy of 7TeV at the LHC. Events containing a single electron or muon and missing transverse momentum are analyzed. No significant excess of events above the standard model expectation is found in the transverse mass distribution of the lepton-neutrino system, and upper limits for cross sections above different transverse mass thresholds are presented. Mass exclusion limits at 95% CL for a range of W' models are determined, including a limit of 2.5TeV for right-handed W' bosons with standard-model-like couplings and limits of 2.43-2.63 TeV for left-handed W' bosons, taking into account their interference with the standard model W boson. Exclusion limits have also been set on Kaluza-Klein W-KK states in the framework of split universal extra dimensions.</P>
Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Asilar, E.,Bergauer, T.,Brandstetter, J.,Brondolin, E.,Dragicevic, M.,Erö,, J.,Flechl, M.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hartl, C.,Hö,rmann, N Springer-Verlag 2017 Journal of high energy physics Vol.2017 No.7
<P>A search is performed for third-generation scalar leptoquarks and heavy right-handed neutrinos in events containing one electron or muon, one hadronically decaying tau lepton, and at least two jets, using a root s = 13 TeV pp collision data sample corresponding to an integrated luminosity of 12: 9 fb(-1) collected with the CMS detector at the LHC in 2016. The number of observed events is found to be in agreement with the standard model prediction. A limit is set at 95% confidence level on the product of the leptoquark pair production cross section and beta(2), where beta is the branching fraction of leptoquark decay to a tau lepton and a bottom quark. Assuming beta = 1, third-generation leptoquarks with masses below 850 GeV are excluded at 95% confidence level. An additional search based on the same event topology involves heavy right-handed neutrinos, N-R, and right-handed W bosons, W-R, arising in a left-right symmetric extension of the standard model. In this search, W-R bosons are assumed to decay to a tau lepton and N-R followed by the decay of the N-R to a tau lepton and an off-shell W-R boson. Assuming the mass of the right-handed neutrino to be half of the mass of the right-handed W boson, W-R boson masses below 2.9 TeV are excluded at 95% confidence level. These results improve on the limits from previous searches for third-generation leptoquarks and heavy right-handed neutrinos with tau leptons in the final state.</P>
Chatrchyan, S.,Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Bergauer, T.,Dragicevic, M.,Erö,, J.,Fabjan, C.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hö,rmann, N.,Hrubec, J.,Jeitler, Springer-Verlag 2013 Journal of high energy physics Vol.2013 No.7
<P>A search for exclusive or quasi-exclusive W+W- production by photon-photon interactions, pp -> p(*)W(+)W(-)p(*), at \/s = 7 TeV is reported using data collected by the CMS detector with an integrated luminosity of 5.05 fb(-1). Events are selected by requiring a mu(+/-)mu(-/+) vertex with no additional associated charged tracks and dilepton transverse momentum p(T)(mu(+/-)mu(-/+)) > 30 GeV. Two events passing all selection requirements are observed in the data, compared to a standard model expectation of 2.2 +/- 0.4 signal events with 0.84 +/- 0.15 background. The tail of the dilepton p(T) distribution is studied for deviations from the standard model. No events are observed with p(T) > 100 GeV. Model-independent upper limits are computed and compared to predictions involving anomalous quartic gauge couplings. The limits on the parameters a(0,c)(W)/A(2) with a dipole form factor and an energy cutoff A(cutoff) = 500 GeV are of the order of 10(-4).</P>
Khachatryan, V.,Sirunyan, A. M.,Tumasyan, A.,Adam, W.,Asilar, E.,Bergauer, T.,Brandstetter, J.,Dragicevic, M.,Erö,, J.,Flechl, M.,Friedl, M.,Frü,hwirth, R.,Ghete, V. M.,Hartl, C.,Hö,rmann, Springer-Verlag 2016 Journal of high energy physics Vol.2016 No.2
<P>A search for a massive resonance decaying into a standard-model-like Higgs boson (H) and a W or Z boson is reported. The analysis is performed on a data sample corresponding to an integrated luminosity of 19.7 fb(-1), collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. Signal events, in which the decay products of Higgs, W, or Z bosons at high Lorentz boost are contained within single reconstructed jets, are identified using jet substructure techniques, including the tagging of b hadrons. This is the first search for heavy resonances decaying into HW or HZ resulting in an all-jet final state, as well as the first application of jet substructure techniques to identify H -> WW* -> 4q decays at high Lorentz boost. No significant signal is observed and limits are set at 95% confidence level on the production cross sections of W' and Z' in a model with mass-degenerate charged and neutral spin-1 resonances. Resonance masses are excluded for W' in the interval [1.0, 1.6] TeV, for Z' in the intervals [1.0, 1.1] and [1.3, 1.5] TeV, and for mass-degenerate W' and Z' in the interval [1.0, 1.7] TeV.</P>