Measurement of the Masses and Lifetimes of B Hadrons at the Tevatron

The latest results for the B Hadron sector at the Tevatron Collider are summarized. The properties of B Hadrons can be precisely measured at the Tevatron. In particularly we will focus on the masses and lifetimes. The new Tevatron results for the CP violation in B Hadrons will be also discussed.Comment: Proceedings of the 40th Rancontres de Moriond QCD and High Energies Hadronic Interactions 2006, 4 pages, 3 figure

Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of $\sqrt s =1.96$ TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is $A_{\mathrm{FB}}^{t\bar{t}} = 0.128 \pm 0.025$. The combined inclusive and differential asymmetries are consistent with recent standard model predictions

"Invariant Mass Distribution of Jet Pairs Produced in Association with a W Boson in ppˉp\bar{p} Collisions at s\sqrt{s} 1.96 TeV"

We present a study of the invariant mass distribution of jet pairs produced in association with a W boson using data collected with the CDF detector which correspond to an integrated luminosity of 4.3 fb$^{−1}$. The observed distribution has an excess in the 120-160 GeV/c$^{2}$ mass range which is not described by current theoretical predictions within the statistical and systematic uncertainties. In particular we will discuss the properties of this excess

Measurement of the top quark mass in the tt¯→ lepton+jets tt¯→ lepton+jets and tt¯→ dilepton tt¯→ dilepton channels using √s=7 TeV ATLAS data

The top quark mass was measured in the channels tt → lepton+jets and tt → dilepton (lepton = e, μ) based on ATLAS data recorded in 2011. The data were taken at the LHC with a proton–proton centre-of-mass energy of √s = 7 TeV and correspond to an integrated luminosity of 4.6 fb−1. The tt → lepton+jets analysis uses a three-dimensional template technique which determines the top quark mass together with a global jet energy scale factor (JSF), and a relative b-to-light-jet energy scale factor (bJSF), where the terms b-jets and light-jets refer to jets originating from b-quarks and u, d, c, s-quarks or gluons, respectively. The analysis of the tt → dilepton channel exploits a one-dimensional template method using the mℓb observable, defined as the average invariant mass of the two lepton+b-jet pairs in each event. The top quark mass is measured to be 172.33 ± 0.75(stat + JSF + bJSF) ± 1.02(syst) GeV, and 173.79 ± 0.54(stat) ± 1.30(syst) GeV in the tt → lepton+jets and tt → dilepton channels, respectively. The combination of the two results yields mtop = 172.99 ± 0.48(stat) ± 0.78(syst) GeV, with a total uncertainty of 0.91 GeV.Physic

Measurement of K T Splitting Scales in W→ℓν Events at √s=7 TeV With the ATLAS Detector

A measurement of splitting scales, as defined by the k T clustering algorithm, is presented for final states containing a W boson produced in proton–proton collisions at a centre-of-mass energy of 7 TeV. The measurement is based on the full 2010 data sample corresponding to an integrated luminosity of 36 pb−1 which was collected using the ATLAS detector at the CERN Large Hadron Collider. Cluster splitting scales are measured in events containing W bosons decaying to electrons or muons. The measurement comprises the four hardest splitting scales in a k T cluster sequence of the hadronic activity accompanying the W boson, and ratios of these splitting scales. Backgrounds such as multi-jet and top-quark-pair production are subtracted and the results are corrected for detector effects. Predictions from various Monte Carlo event generators at particle level are compared to the data. Overall, reasonable agreement is found with all generators, but larger deviations between the predictions and the data are evident in the soft regions of the splitting scales.Physic