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Abstract:

We search for new long-lived particles which decay to Z0 bosons by looking tor Z0→e+e- decays with displaced vertices. We find no evidence for parent particles of the Z0 with long lifetimes in 90 pb-1 of data from the CDF experiment at Fermilab. We set a cross section limit as a function of the lifetime of the parent particle for both a generic Z0 parent and a fourth-generation, charge -1/3 quark that decays into Z0b.

Abstract:

The average bottom-hadron and individual (Formula presented), (Formula presented), and (Formula presented) meson lifetimes have been determined using decays with a (Formula presented) in the final state. The data sample consists of 110 pb(Formula presented) of (Formula presented) collisions at (Formula presented) TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992–1995. For the average lifetime of (Formula presented) hadrons decaying into (Formula presented)+X, we obtain (Formula presented) For the (Formula presented) and (Formula presented) meson lifetimes, we determine (Formula presented) (Formula presented) and (Formula presented) For the (Formula presented) meson lifetime, we find (Formula presented) ps. © 1998 The American Physical Society.

Abstract:

The lifetimes of the B- and B̄0 mesons are measured using the partially reconstructed semileptonic decays B̄ → Dl- v̄X, where D0 is either a D0 or D*+ meson. The data were collected by the CDF detector at the Fermilab Tevatron collider during 1992-1995 and correspond to about 110 pb-1 of pp collisions at √s = 1.8 TeV. We measure decay lengths and extract the lifetimes to be τ(B-) = 1.637±0.058-0.043+0.045 ps and τ(B̄0) = 1.474±0.039-0.051+0.052 ps, and the ratio of the lifetimes to be τ(B-)/τ(B̄0) = 1.110±0.056-0.030+0.033, where the first uncertainties are statistical and the second are systematic.

Abstract:

We present a measurement of the B⁰ ↔ B^-0 oscillation frequency using a flavor tagging method based on correlations of B meson flavor with the charge of other particles produced in pp collisions at √ s = 1.8 TeV. Such correlations are expected to arise from b quark hadronization and from B** decays. We partially reconstruct B mesons using the semileptonic decays B⁰ → l⁺D^(*)-X and B⁺ → l⁺D^-0X. From the oscillation frequency, we obtain the mass difference between the two B⁰ mass eigenstates, Δmd = 0.471^+0.078 -0.068(stat) ± 0.034(syst) ħps^-1, and measure the efficiency and purity of this flavor tagging method for both charged and neutral B mesons. © 1998 The American Physical Society.

Abstract:

We present the first general measurements (invariant-mass, transverse-energy, and angular distributions) of the process, (Formula presented) (Formula presented) using data collected by the CDF at Fermilab. We compare the data with predictions from a tree-level QCD calculation and the PYTHIA shower Monte Carlo program. Our data sample is particularly sensitive to contributions from initial- and final-state radiation of photons and jets. Using the PYTHIA Monte Carlo program, we contrast the kinematical distributions for direct photon production with those for initial- and final-state photon radiation (bremsstrahlung). Based on the angular distributions, we find that our data favor a mixture of bremsstrahlung and direct photon production, as predicted, over either process alone. © 1998 The American Physical Society.