A search is presented for physics beyond the standard model (BSM) in events with a Z boson, jets, and missing transverse energy (E T miss). This signature is motivated by BSM physics scenarios, ...including supersymmetry. The study is performed using a sample of proton-proton collision data collected at s = 7 TeV with the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.98 fb-1. The contributions from the dominant standard model backgrounds are estimated from data using two complementary strategies, the jet-Z balance technique and a method based on modeling E T miss with data control samples. In the absence of evidence for BSM physics, we set limits on the non-standard-model contributions to event yields in the signal regions and interpret the results in the context of simplified model spectra. Additional information is provided to facilitate tests of other BSM physics models.
The results of a search for pair production of a heavy, top-like quark, t ' , in the decay mode t ' t A= ' ? bW + b A= W - ? b l + ? b A= l - ? A= are presented. The search is performed with a data ...sample corresponding to an integrated luminosity of 5.0 fb - 1 in pp collisions at a center-of-mass energy of 7 TeV, collected by the CMS experiment at the LHC. The observed number of events agrees with the expectation from standard model processes, and no evidence of t ' t A= ' production is found. Upper limits on the production cross section as a function of t ' mass are presented, and t ' masses below 557 GeV / c 2 are excluded at the 95% confidence level.
A search for neutral Higgs bosons decaying to tau pairs at a center-of-mass energy of 7 TeV is performed using a dataset corresponding to an integrated luminosity of 4.6 fba1 recorded by the CMS ...experiment at the LHC. The search is sensitive to both the standard model Higgs boson and to the neutral Higgs bosons predicted by the minimal supersymmetric extension of the standard model (MSSM). No excess of events is observed in the tau-pair invariant-mass spectrum. For a standard model Higgs boson in the mass range of 110a145 GeV upper limits at 95% confidence level (CL) on the production cross section are determined. We exclude a Higgs boson with m H = 115 GeV with a production cross section 3.2 times of that predicted by the standard model. In the MSSM, upper limits on the neutral Higgs boson production cross section times branching fraction to tau pairs, as a function of the pseudoscalar Higgs boson mass, m A , sets stringent new bounds in the parameter space, excluding at 95% CL values of tan I2 as low as 7.1 at m A = 160 GeV in the m h max benchmark scenario.
Dijet production in PbPb collisions at a nucleonanucleon center-of-mass energy of 2.76 TeV is studied with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 150 ...I14ba1 is analyzed. Jets are reconstructed using combined information from tracking and calorimetry, using the anti- k T algorithm with R = 0.3 . The dijet momentum balance and angular correlations are studied as a function of collision centrality and leading jet transverse momentum. For the most peripheral PbPb collisions, good agreement of the dijet momentum balance distributions with pp data and reference calculations at the same collision energy is found, while more central collisions show a strong imbalance of leading and subleading jet transverse momenta attributed to the jet-quenching effect. The dijets in central collisions are found to be more unbalanced than the reference, for leading jet transverse momenta up to the highest values studied.
Results are presented from a search for large, extra spatial dimensions in events with either two isolated muons or two isolated electrons. The data are from proton-proton interactions at s = 7 TeV ...collected with the CMS detector at the LHC. The size of the data sample corresponds to an integrated luminosity of approximately 2 fb - 1 . The observed dimuon and dielectron mass spectra are found to be consistent with standard-model expectations. Depending on the number of extra dimensions, the 95% confidence level limits from the combined mu mu and ee channels range from M s > 2.4 TeV to M s > 3.8 TeV , where M s characterizes the scale for the onset of quantum gravity.
A measurement of the t production cross section in proton-proton collisions at a centre-of-mass energy of 7 TeV has been performed at the LHC with the CMS detector. The analysis uses a data sample ...corresponding to an integrated luminosity of 36 pb super(-1) and is based on the reconstruction of the final state with one isolated, high transverse-momentum electron or muon and three or more hadronic jets. The kinematic properties of the events are used to separate the t signal from W+jets and QCD multijet background events. The measured cross section is 173+39}_{-32} + consistent with standard model expectations.
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