B. Auerbach

Measurement of the differential cross section dσ/ d(cos□θt) for top-quark pair production in pp̄ collisions at √s=1.96 TeV

We report a measurement of the differential cross section dσ/d(cosθ(t)) for top-quark pair production as a function of the top-quark production angle in proton-antiproton collisions at sqrt[s] = 1.96 TeV. This measurement is performed using data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.4 fb(-1). We employ the Legendre polynomials to characterize the shape of the differential cross section at the parton level. The observed Legendre coefficients are in good agreement with the prediction of the next-to-leading-order standard-model calculation, with the exception of an excess linear-term coefficient a(1) = 0.40 ± 0.12, compared to the standard-model prediction of a(1)=0.15(-0.03)(+0.07).

FTK: a Fast Track Trigger for ATLAS

We describe the design and expected performance of a the Fast Tracker Trigger (FTK) system for the ATLAS detector at the Large Hadron Collider. The FTK is a highly parallel hardware system designed to operate at the Level 1 trigger output rate. It is designed to provide global tracks reconstructed in the inner detector with resolution comparable to the full offline reconstruction as input of the Level 2 trigger processing. The hardware system is based on associative memories for pattern recognition and fast FPGAs for track reconstruction. The FTK is expected to dramatically improve the performance of track based isolation and b-tagging with little to no dependencies of pile-up interactions.

Improved determination of the sample composition of dimuon events produced in pp̄ collisions at √s=1.96 TeV - eScholarship

We use a new method to estimate with 5% accuracy the contribution of pion and kaon in-flight-decays to the dimuon data set acquired with the CDF detector. Based on this improved estimate, we show that the total number and the properties of the collected dimuon events are not yet accounted for by ordinary sources of dimuons which also include the contributions, as measured in the data, of heavy flavor, ϒ, and Drell–Yan production in addition to muons mimicked by hadronic punchthrough. The number of unaccounted events corresponds to (12.8±3.2)% of the

Search for a Two-Higgs-Boson Doublet Using a Simplified Model in pp̄ Collisions at √s=1.96 TeV

b\bar{b}

A fast hardware tracker for the ATLAS trigger system

production. We find that (23±6)% of the unaccounted events contain additional muon candidates. For comparison, this fraction is (6.9±0.4)% for events due to

Search for Heavy Bottomlike Quarks Decaying to an Electron or Muon

b\bar{b}

Evidence for t tproduction and measurement oft t = t t

production.