A search for the production of heavy partners of the top quark with charge 5/3 is performed in ev... more A search for the production of heavy partners of the top quark with charge 5/3 is performed in events with a pair of same-sign leptons. The data sample corresponds to an integrated luminosity of 19.5 fb −1 and was collected at √ s = 8 TeV by the CMS experiment. No significant excess is observed in the data above the expected background and the existence of top-quark partners with masses below 800 GeV is excluded at a 95% confidence level, assuming they decay exclusively to tW. This is the first limit on these particles from the LHC, and it is significantly more restrictive than previous limits.
Abstract A search for new exotic particles decaying to the VZ final state is performed, where V i... more Abstract A search for new exotic particles decaying to the VZ final state is performed, where V is either a W or a Z boson decaying into two overlapping jets and the Z decays into a pair of electrons, muons or neutrinos. The analysis uses a data sample of pp collisions ...
A search for supersymmetry is presented using a sample of events with b jets and missing transver... more A search for supersymmetry is presented using a sample of events with b jets and missing transverse momentum. The search uses a data sample of proton-proton collisions at a centre-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 35 pb −1 , collected with the CMS detector. A total of 0.33 +0.43 −0.33 (stat.) ± 0.13 (syst.) events is predicted, using control samples in the data, to arise from standard model processes, and one event is observed in the data. Upper limits are set at the 95% confidence level on the cross sections of benchmark supersymmetric models.
The results of searches for new physics in events with two same-sign isolated leptons, hadronic j... more The results of searches for new physics in events with two same-sign isolated leptons, hadronic jets, and missing transverse energy in the final state are presented. The searches use an integrated luminosity of 35 pb −1 of pp collision data at a centre-of-mass energy of 7 TeV collected by the CMS experiment at the LHC. The observed numbers of events agree with the standard model predictions, and no evidence for new physics is found. To facilitate the interpretation of our data in a broader range of new physics scenarios, information on our event selection, detector response, and efficiencies is provided.
Azimuthal dihadron correlations of charged particles have been measured in PbPb collisions at √ s... more Azimuthal dihadron correlations of charged particles have been measured in PbPb collisions at √ s NN = 2.76 TeV by the CMS collaboration, using data from the 2011 LHC heavy-ion run. The data set includes a sample of ultra-central (0-0.2% centrality) PbPb events collected using a trigger based on total transverse energy in the hadron forward calorimeters and the total multiplicity of pixel clusters in the silicon pixel tracker. A total of about 1.8 million ultra-central events were recorded, corresponding to an integrated luminosity of 120 µb −1 . The observed correlations in ultra-central PbPb events are expected to be particularly sensitive to initial-state fluctuations. The single-particle anisotropy Fourier harmonics, from v 2 to v 6 , are extracted as a function of particle transverse momentum. At higher transverse momentum, the v 2 harmonic becomes significantly smaller than the higher-order v n (n ≥ 3). The p T -averaged v 2 and v 3 are found to be equal within 2%, while higher-order v n decrease as n increases. The breakdown of factorization of dihadron correlations into single-particle azimuthal anisotropies is observed. This effect is found to be most prominent in the ultra-central PbPb collisions, where the initial-state fluctuations play a dominant role. A comparison of the factorization data to hydrodynamic predictions with event-byevent fluctuating initial conditions is also presented. Submitted to the Journal of High Energy Physics c 2013 CERN for the benefit of the CMS Collaboration. CC-BY-3.0 license arXiv:1312.1845v1 [nucl-ex]
A search for the production of heavy partners of the top quark with charge 5/3 is performed in ev... more A search for the production of heavy partners of the top quark with charge 5/3 is performed in events with a pair of same-sign leptons. The data sample corresponds to an integrated luminosity of 19.5 fb −1 and was collected at √ s = 8 TeV by the CMS experiment. No significant excess is observed in the data above the expected background and the existence of top-quark partners with masses below 800 GeV is excluded at a 95% confidence level, assuming they decay exclusively to tW. This is the first limit on these particles from the LHC, and it is significantly more restrictive than previous limits.
Abstract A search for new exotic particles decaying to the VZ final state is performed, where V i... more Abstract A search for new exotic particles decaying to the VZ final state is performed, where V is either a W or a Z boson decaying into two overlapping jets and the Z decays into a pair of electrons, muons or neutrinos. The analysis uses a data sample of pp collisions ...
A search for supersymmetry is presented using a sample of events with b jets and missing transver... more A search for supersymmetry is presented using a sample of events with b jets and missing transverse momentum. The search uses a data sample of proton-proton collisions at a centre-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 35 pb −1 , collected with the CMS detector. A total of 0.33 +0.43 −0.33 (stat.) ± 0.13 (syst.) events is predicted, using control samples in the data, to arise from standard model processes, and one event is observed in the data. Upper limits are set at the 95% confidence level on the cross sections of benchmark supersymmetric models.
The results of searches for new physics in events with two same-sign isolated leptons, hadronic j... more The results of searches for new physics in events with two same-sign isolated leptons, hadronic jets, and missing transverse energy in the final state are presented. The searches use an integrated luminosity of 35 pb −1 of pp collision data at a centre-of-mass energy of 7 TeV collected by the CMS experiment at the LHC. The observed numbers of events agree with the standard model predictions, and no evidence for new physics is found. To facilitate the interpretation of our data in a broader range of new physics scenarios, information on our event selection, detector response, and efficiencies is provided.
Azimuthal dihadron correlations of charged particles have been measured in PbPb collisions at √ s... more Azimuthal dihadron correlations of charged particles have been measured in PbPb collisions at √ s NN = 2.76 TeV by the CMS collaboration, using data from the 2011 LHC heavy-ion run. The data set includes a sample of ultra-central (0-0.2% centrality) PbPb events collected using a trigger based on total transverse energy in the hadron forward calorimeters and the total multiplicity of pixel clusters in the silicon pixel tracker. A total of about 1.8 million ultra-central events were recorded, corresponding to an integrated luminosity of 120 µb −1 . The observed correlations in ultra-central PbPb events are expected to be particularly sensitive to initial-state fluctuations. The single-particle anisotropy Fourier harmonics, from v 2 to v 6 , are extracted as a function of particle transverse momentum. At higher transverse momentum, the v 2 harmonic becomes significantly smaller than the higher-order v n (n ≥ 3). The p T -averaged v 2 and v 3 are found to be equal within 2%, while higher-order v n decrease as n increases. The breakdown of factorization of dihadron correlations into single-particle azimuthal anisotropies is observed. This effect is found to be most prominent in the ultra-central PbPb collisions, where the initial-state fluctuations play a dominant role. A comparison of the factorization data to hydrodynamic predictions with event-byevent fluctuating initial conditions is also presented. Submitted to the Journal of High Energy Physics c 2013 CERN for the benefit of the CMS Collaboration. CC-BY-3.0 license arXiv:1312.1845v1 [nucl-ex]
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