Professor Daniela Bortoletto

Abstract:

We present a measurement of RB, the ratio of the branching fraction for the rare decay D0→K+π- to that for the Cabibbo-favored decay D0→K-π+. Charge-conjugate decays are implicitly included. A signal of 2005±104 events for the decay D0→K+π- is obtained using the CDF II detector at the Fermilab Tevatron collider. The data set corresponds to an integrated luminosity of 0.35fb-1 produced in p̄p collisions at s=1.96TeV. Assuming no mixing, we find RB=[4.05±0.21(stat)±0.11(syst)] ×10-3. This measurement is consistent with the world average, and comparable in accuracy with the best measurements from other experiments. © 2006 The American Physical Society.

Abstract:

We describe a measurement of the top quark mass using events with two charged leptons collected by the CDF II detector from pp̄ collisions with s=1.96TeV at the Fermilab Tevatron. The likelihood in top quark mass is calculated for each event by convoluting the leading order matrix element describing qq̄→tt̄→blνlb̄l′νl′ with detector resolution functions. The presence of background events in the data sample is modeled using similar calculations involving the matrix elements for major background processes. In a data sample with integrated luminosity of 340pb-1, we observe 33 candidate events and measure Mtop=165.2±6.1(stat.) ±3.4(syst.)GeV/c2. This measurement represents the first application of this method to events with two charged leptons and is the most precise single measurement of the top quark mass in this channel. © 2006 The American Physical Society.

Abstract:

We present a measurement of the top quark pair production cross section in pp̄ collisions at s=1.96TeV using 318pb-1 of data collected with the Collider Detector at Fermilab. We select tt̄ decays into the final states eν+jets and μν+jets, in which at least one b quark from the t-quark decays is identified using a secondary vertex-finding algorithm. Assuming a top quark mass of 178GeV/c2, we measure a cross section of 8.7±0.9(stat)-0. 9+1.1(syst)pb. We also report the first observation of tt̄ with significance greater than 5σ in the subsample in which both b quarks are identified, corresponding to a cross section of 10.1-1.4+1.6(stat)-1.3+2.0(syst) pb. © 2006 The American Physical Society.

Abstract:

We present the results of a search for standard model Higgs boson production with decay to WW*, identified through the leptonic final states e+e-ν̄ν,e±μ.