arXiv subjects
Publications and source records attributed to Gavril Giurgiu.
The D0 and CDF detectors at the Fermilab Tevatron have each accumulated more that 9/fb of integrated luminosity. The corresponding large datasets enable the two experiments to perform unprecedented studies of heavy flavor hadron properties. We present recent D0 and CDF measurements, focusing on rare decays and CP violation in B-meson decays.
The CDF collaboration presents an updated measurement of the CP-violating parameter beta_s and of the decay width difference Delta Gamma_s using approximately 6500 Bs to J/Psi Phi decays collected by the dimuon trigger and reconstructed in a data sample corresponding to 5.2/fb of integrated luminosity. Besides exploiting the two-fold increase in the data sample with respect to the previous measurement, several improvements have been introduced in the analysis including a fully data-driven flavor tagging calibration and proper treatment of possible S-wave contributions. We find that the CP-violating phase is within the range beta_s in [0.02, 0.52] U [1.08,1.55] at 68C.L. The Standard Model p-value is 0.31. The decay width difference is found to be Delta Gamma_s = 0.075 +/- 0.035 (stat) +/- 0.01 syst 1/ps. In addition, we present the most precise mean Bs lifetime tau_s, polarization amplitudes |A_0|^2, |A_{\parallel}|^2 and |A_{\perp}|^2, as well as strong phase delta_perp: tau_s = 458.6 +/- 7.6$ (stat) +/- 3.6 (syst) microns |A_0|^2 = 0.524 +/- 0.013 (stat) +/- 0.015 (syst) |A_{\parallel}|^2 = 0.231 +/- 0.014 (stat) +/- 0.015 (syst) delta_perp = 2.95 +/- 0.64 (stat) +/- 0.07 (syst).
We present measurements of the branching ratio and of the polarization amplitudes in charmless Bs to Phi Phi decays using data corresponding to 2.9/fb of integrated luminosity, collected by the CDF experiment at the Tevatron. The branching ratio in Bs to Phi Phi decays is measured relative to the normalization mode Bs to J/Psi Phi$ to be B(Bs to Phi Phi)/B(Bs to J/Psi Phi) = [1.78 +/- 0.14 (stat) +/- 0.20 (syst)] x 10^{-2}. Using the experimental value of B(Bs to J/Psi Phi) we determine the Bs to Phi Phi branching ratio B(Bs to Phi Phi) = 2.40 +/- 0.21(stat) +/- 0.27(syst) +/- 0.82 (BR)] x 10^{-5}. The polarization fractions are measured for the first time in this analysis and found to be: |A_0|^2 = 0.348 +/- 0.041 (stat) +/- 0.021 (syst) |A_parallel|^2 = 0.287 +/- 0.043 (stat) +/- 0.011 (syst) |A_perp|^2 = 0.365 +/- 0.044 (stat) +/- 0.027 (syst).
High mass resonances decaying into ttbar pairs appear in many extensions of the Standard Model. The top quarks from these decays have high transverse momenta and their decay products are highly collimated due to the boost into the lab frame. As a result the standard techniques for reconstructing ttbar events begin to fail. In this talk we discuss the prospects for detecting booted top quarks at CMS. A new top jet tagging algorithm is presented. This algorithm achieves an efficiency of 46% for boosted top jets and rejection of 98.5% for generic QCD jets with transverse momenta of 600 GeV/$c$.
We present recent CDF measurements of mass, lifetime and CP violation properties of B hadrons. The analyzes presented in this paper use up to 2.8/fb of data. CDF has already accumulated close to 5/fb of data which promises significant improvements of these analyzes in the near future.
The CDF detector at Fermilab has accumulated more that 3/fb of data which enables unprecedented studies of heavy flavor hadron properties. We present recent CDF measurements of mass and lifetime of the Bc meson as well as lifetime, mixing and CP violation properties of Bs mesons.