33 research outputs found
Searches for supersymmetry based on events with b jets and four W bosons in pp collisions at 8 TeV
Five mutually exclusive searches for supersymmetry are presented based on events in which b jets and four W bosons are produced in proton-proton collisions at root s = 8TeV. The data, corresponding to an integrated luminosity of 19.5 fb(-1), were collected with the CMS experiment at the CERN LHC in 2012. The five studies differ in the leptonic signature from the W boson decays, and correspond to all-hadronic, single-lepton, opposite-sign dilepton, same-sign dilepton, and >= 3 lepton final states. The results of the five studies are combined to yield 95% confidence level limits for the gluino and bottom-squark masses in the context of gluino and bottom-squark pair production, respectively. In the limit when the lightest supersymmetric particle is light, gluino and bottom squark masses are excluded below 1280 and 570 GeV, respectively
Search for supersymmetry in pp collisions at in events with a single lepton, large jet multiplicity, and multiple b jets
Results are reported from a search for supersymmetry in pp collisions at a center-of-mass energy of 8 TeV, based on events with a single isolated lepton (electron or muon) and multiple jets, at least two of which are identified as b jets. The data sample corresponds to an integrated luminosity of 19.3 fb(-1) recorded by the CMS experiment at the LHC in 2012. The search is motivated by supersymmetric models that involve strong-production processes and cascade decays of new particles. The resulting final states contain multiple jets as well as missing transverse momentum from weakly interacting particles. The event yields, observed across several kinematic regions, are consistent with the expectations from standard model processes. The results are interpreted in the context of simplified supersymmetric scenarios with pair production of gluinos, where each gluino decays to a top quark-antiquark pair and the lightest neutralino. For the case of decays via virtual top squarks, gluinos with a mass smaller than 1.26 TeV are excluded for low neutralino masses
Evidence on a DSGE Business Cycle Model Subject to Neutral and Investment-Specific Technology Shocks Using Bayesian Model Averaging
Search for new resonances decaying via WZ to leptons in proton-proton collisions at root s=8 TeV
A search is performed in proton-proton collisions at root s = 8 TeV for exotic particles decaying via WZ to fully leptonic final states with electrons, muons, and neutrinos. The data set corresponds to an integrated luminosity of 19.5 fb(-1). No significant excess is observed above the expected standard model background. Upper bounds at 95% confidence level are set on the production cross section of a W boson as predicted by an extended gauge model, and on the W'WZ coupling. The expected and observed mass limits for a W' boson, as predicted by this model, are 1.55 and 1.47 TeV, respectively. Stringent limits are also set in the context of low-scale technicolor models under a range of assumptions for the model parameters
Search for a standard model-like Higgs boson in the mu(+)mu(-) and e(+)e(-) decay channels at the LHC
A search is presented for a standard model-like Higgs boson decaying to the mu(+)mu(-) or e(+)e(-) final states based on proton-proton collisions recorded by the CMS experiment at the CERN LHC. The data correspond to integrated luminosities of 5.0 fb(-1) at a centre-of-mass energy of 7 TeV and 19.7 fb(-1) at 8 TeV for the mu(+)mu(-) search, and of 19.7 fb(-1) at 8 TeV for the e(+)e(-) search. Upper limits on the production cross section times branching fraction at the 95% confidence level are reported for Higgs boson masses in the range from 120 to 150 GeV. For a Higgs boson with a mass of 125 GeV decaying to mu(+)mu(-), the observed (expected) upper limit on the production rate is found to be 7.4 (6.5(-1.9)(+2.8)) times the standard model value. This corresponds to an upper limit on the branching fraction of 0.0016. Similarly, for e(+)e(-), an upper limit of 0.0019 is placed on the branching fraction, which is approximate to 3.7 x 10(5) times the standard model value. These results, together with recent evidence of the 125 GeV boson coupling to tau-leptons with a larger branching fraction consistent with the standard model, confirm that the leptonic couplings of the new boson are not flavour-universal
Search for top-squark pairs decaying into Higgs or Z bosons in pp collisions at root s=8 TeV
A search for supersymmetry through the direct pair production of top squarks, with Higgs (H) or Z bosons in the decay chain, is performed using a data sample of proton-proton collisions at root s = 8 TeVcollected in 2012 with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 19.5 fb(-1). The search is performed using a selection of events containing leptons and bottom-quark jets. No evidence for a significant excess of events over the standard model background prediction is observed. The results are interpreted in the context of simplified supersymmetric models with pair production of a heavier top-squark mass eigenstate (t) over tilde (2) decaying to a lighter top-squark mass eigenstate (t) over tilde (1) via either (t) over tilde (2) -> H (t) over tilde (1) or (t) over tilde (2) -> Z (t) over tilde (1), followed in both cases by (t) over tilde (1) -> t (chi) over tilde (0)(1), where (chi) over tilde (0)(1) is an undetected, stable, lightest supersymmetric particle. The interpretation is performed in the region where the mass difference between the (t) over tilde (1) and (chi) over tilde (0)(1) states is approximately equal to the top-quark mass (m((t) over tilde )1) - m((chi) over tilde 10) similar or equal to m(t)) which is not probed by searches for direct (t) over tilde (1) squark pair production. The analysis excludes top squarks with masses m((t) over tilde2) 1) < 400 GeVat a 95% confidence level
