Model-independent determination of the strong-phase difference between D0 and D⊃̄0→KS,L0h+h- (h=π, K) and its impact on the measurement of the CKM angle γ/Φ3
Physical Review D - Particles, Fields, Gravitation and Cosmology 82:11 (2010)
Abstract:
We report the first determination of the relative strong-phase difference between D0→KS,L0K+K- and D⊃̄0→KS, L0K+K-. In addition, we present updated measurements of the relative strong-phase difference between D0→KS, L0π+π- and D⊃̄0→KS,L0π +π-. Both measurements exploit the quantum coherence between a pair of D0 and D⊃̄0 mesons produced from ψ(3770) decays. The strong-phase differences measured are important for determining the Cabibbo-Kobayashi-Maskawa angle γ/Φ3 in B -→K-D⊃0 decays, where D⊃0 is a D0 or D⊃̄0 meson decaying to KS0h+h- (h=π, K), in a manner independent of the model assumed to describe the D0→KS0h +h- decay. Using our results, the uncertainty in γ/Φ3 due to the error on the strong-phase difference is expected to be between 1.7° and 3.9° for an analysis using B -→K-D⊃0, D⊃0→KS0π+π - decays, and between 3.2° and 3.9° for an analysis based on B-→K-D⊃0, D⊃0→KS0K+K - decays. A measurement is also presented of the CP-odd fraction, F-, of the decay D0→KS0K+K- in the region of the Φ→K+K- resonance. We find that in a region within 0.01GeV2/c4 of the nominal Φ mass squared F->0.91 at the 90% confidence level. © 2010 The American Physical Society.Search for quark compositeness with the dijet centrality ratio in pp collisions at √s=7TeV
Physical Review Letters 105:26 (2010)
Abstract:
A search for quark compositeness in the form of quark contact interactions, based on hadronic jet pairs (dijets) produced in proton-proton collisions at √s=7TeV, is described. The data sample of the study corresponds to an integrated luminosity of 2.9pb⊃-1 collected with the CMS detector at the LHC. The dijet centrality ratio, which quantifies the angular distribution of the dijets, is measured as a function of the invariant mass of the dijet system and is found to agree with the predictions of the standard model. A statistical analysis of the data provides a lower limit on the energy scale of quark contact interactions. The sensitivity of the analysis is such that the expected limit is 2.9 TeV; because the observed value of the centrality ratio at high invariant mass is below the expectation, the observed limit is 4.0 TeV at the 95% confidence level. © 2010 CERN, for the CMS Collaboration.Erratum: Measurement of particle production and inclusive differential cross sections in pp̄ collisions at √s=1.96TeV (Physical Review D - Particles, Fields, Gravitation and Cosmology)
Physical Review D - Particles, Fields, Gravitation and Cosmology 82:11 (2010)
Top quark mass measurement in the lepton + jets channel using a matrix element method and in situ jet energy calibration.
Phys Rev Lett 105:25 (2010) 252001
Abstract:
A precision measurement of the top quark mass m(t) is obtained using a sample of tt events from pp collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, large missing transverse energy, and exactly four high-energy jets, at least one of which is tagged as coming from a b quark. A likelihood is calculated using a matrix element method with quasi-Monte Carlo integration taking into account finite detector resolution and jet mass effects. The event likelihood is a function of m(t) and a parameter Δ(JES) used to calibrate the jet energy scale in situ. Using a total of 1087 events in 5.6 fb(-1) of integrated luminosity, a value of m(t)=173.0 ± 1.2 GeV/c(2) is measured.Observation of single top quark production and measurement of
Physical Review D - Particles, Fields, Gravitation and Cosmology 82:11 (2010)