Search for a narrow, spin-2 resonance decaying to a pair of Z bosons in the qq̄ℓ+ℓ- final state
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 718:4-5 (2013) 1208-1228
Abstract:
Results are presented from a search for a narrow, spin-2 resonance decaying into a pair of Z bosons, with one Z-boson decaying into leptons (e+e- or μ+μ-) and the other into jets. An example of such a resonance is the Kaluza-Klein graviton, GKK, predicted in Randall-Sundrum models. The analysis is based on a 4.9 fb-1 sample of proton-proton collisions at a center-of-mass energy of 7 TeV, collected with the CMS detector at the LHC. Kinematic and topological properties including decay angular distributions are used to discriminate between signal and background. No evidence for a resonance is observed, and upper limits on the production cross sections times branching fractions are set. In two models that predict Z-boson spin correlations in graviton decays, graviton masses are excluded lower than a value which varies between 610 and 945 GeV, depending on the model and the strength of the graviton couplings. © 2012 CERN.Search for flavor changing neutral currents in top quark decays in pp collisions at 7 TeV
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 718:4-5 (2013) 1252-1272
Abstract:
The results of a search for flavor changing neutral currents in top quark decays t→Zq in events with a topology compatible with the decay chain tt̄→Wb+Zq→ℓνb+ℓℓq are presented. The search is performed with a data sample corresponding to an integrated luminosity of 5.0 fb-1 of proton-proton collisions at a center-of-mass energy of 7 TeV, collected with the CMS detector at the LHC. The observed number of events agrees with the standard model prediction and no evidence for flavor changing neutral currents in top quark decays is found. A t→Zq branching fraction greater than 0.21% is excluded at the 95% confidence level. © 2012 CERN.Measurement of the top-antitop production cross section in the tau+jets channel in pp collisions at sqrt(s) = 7 TeV
ArXiv 1301.5755 (2013)
Measurement of the azimuthal anisotropy of neutral pions in Pb-Pb collisions at √sNN =2.76 TeV
Physical Review Letters 110:4 (2013)
Abstract:
First measurements of the azimuthal anisotropy of neutral pions produced in Pb-Pb collisions at a center-of-mass energy of √sNN=2.76 TeV are presented. The amplitudes of the second Fourier component (v2) of the π0 azimuthal distributions are extracted using an event-plane technique. The values of v2 are studied as a function of the neutral pion transverse momentum (pT) for different classes of collision centrality in the kinematic range 1.6Search for contact interactions using the inclusive jet pT spectrum in pp collisions at sqrt(s) = 7 TeV
ArXiv 1301.5023 (2013)