Analysis of the decay D0→KS0π0π0
Physical Review D - Particles, Fields, Gravitation and Cosmology 84:9 (2011)
Abstract:
We present the results of a Dalitz plot analysis of D0→KS0π0π0 using the CLEO-c data set of 818pb-1 of e+e- collisions accumulated at √s=3.77GeV. This corresponds to 3×106 D0D̄0 pairs from which we select 1259 tagged candidates with a background of 7.5±0.9 percent. Several models have been explored, all of which include the K*(892), K2*(1430), K *(1680), the f0(980), and the σ(500). We find that the combined π0π0 S-wave contribution to our preferred fit is (28.9±6.3±3.1)% of the total decay rate while D0→K ̄*(892)0π0 contributes (65.6±5. 3±2.5)%. Using three tag modes and correcting for quantum correlations we measure the D0→KS0π0π0 branching fraction to be (1.058±0. 038±0.073)%. © 2011 American Physical Society.Measurement of the tt̄ production cross section in pp collisions at 7 TeV in lepton+jets events using b-quark jet identification
Physical Review D - Particles, Fields, Gravitation and Cosmology 84:9 (2011)
Abstract:
A new measurement of the inclusive production cross section for pp→tt̄ is performed at a center-of-mass energy of 7 TeV using data collected by the CMS experiment at the LHC. The analysis uses a data sample corresponding to an integrated luminosity of 36pb-1, and is based on the final state with one isolated, high transverse momentum muon or electron, missing transverse energy, and hadronic jets. The tt̄ content of the selected events is enhanced by requiring the presence of at least one jet consistent with b-quark hadronization. The measured cross section is 150±9(stat)±17(syst)±6(lumi)pb and is in agreement with higher-order QCD calculations. The combination of this measurement with a previous CMS result based on dileptons gives 154±17(stat+syst) ±6(lumi)pb. © 2011 CERN.Search for new physics with a monojet and missing transverse energy in pp collisions at √s=7TeV
Physical Review Letters 107:20 (2011)
Abstract:
A study of events with missing transverse energy and an energetic jet is performed using pp collision data at a center-of-mass energy of 7 TeV. The data were collected by the CMS detector at the LHC, and correspond to an integrated luminosity of 36pb-1. An excess of these events over standard model contributions is a signature of new physics such as large extra dimensions and unparticles. The number of observed events is in good agreement with the prediction of the standard model, and significant extension of the current limits on parameters of new physics benchmark models is achieved. © 2011 CERN.Observation of the baryonic flavor-changing neutral current decay Λb0→Λμ+μ-
Physical Review Letters 107:20 (2011)
Abstract:
We report the first observation of the baryonic flavor-changing neutral current decay Λb0→Λμ+μ- with 24 signal events and a statistical significance of 5.8 Gaussian standard deviations. This measurement uses a pp̄ collisions data sample corresponding to 6.8fb-1 at √s=1.96TeV collected by the CDF II detector at the Tevatron collider. The total and differential branching ratios for Λb0→Λμ+μ- are measured. We find B(Λb0→Λμ+μ-)=[1.73±0. 42(stat)±(syst)]×10-6. We also report the first measurement of the differential branching ratio of Bs0→μ+μ -, using 49 signal events. In addition, we report branching ratios for B+→K+μ+μ-, B0→K0μ+μ-, and B→K*(892) μ+μ- decays. © 2011 American Physical Society.J/psi and psi(2S) production in pp collisions at sqrt(s) = 7 TeV
ArXiv 1111.1557 (2011)