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

Verification of simulated ASIC functionality and radiation tolerance for the HL-LHC ATLAS ITk Strip Detector

ASICs are important components in many HEP detectors and their functional simulation ensures successful operation while minimizing the number of long production cycles. Three radiation-tolerant ASICs (HCC, AMAC, and ABC) will perform the front-end readout, monitoring, and control of the outer layers of the ITk Strip particle tracker for the HL-LHC ATLAS detector. Simulated verification with the Python-based cocotb framework allows for sophisticated tests with major contributions from students and firmware non-experts. The verification program includes interactions between multiple ASICs, realistic HL-LHC data flows, operational stress tests, and a focus on mitigation of disruptive Single Event Effects due to radiation

Testing of the HCC and AMAC functionality and radiation tolerance for the HL-LHC ATLAS ITk Strip Detector

The ITk Strip is a new silicon-strip charged-particle detector for the HL-LHC ATLAS experiment. The HCC and AMAC chip are radiation-tolerant ASICs that contribute to the front-end readout, monitoring and control of the ITk Strip. Comprehensive functionality tests have been performed on HCC and AMAC to guarantee their reliability throughout the HL-LHC lifetime. In addition, to ensure the operation of the HCC and AMAC under a radiation heavy environment, gamma, heavy ions, proton and x-ray irradiation campaigns were conducted. HCC and AMAC successfully operated at extreme conditions and were reliable at the expected HL-LHC conditions

Irradiation testing of ASICs for the ATLAS HL-LHC upgrade

For the high-luminosity upgrade to the LHC, the ATLAS Inner Detector will be replaced by an all-silicon tracker (ITk) consisting of two systems: pixels and strips. HCC and AMAC are ITk Strip ASICs vital for performing the system readout, monitoring, and control. To ensure these ASICs will successfully operate in the high-radiation environment of the HL-LHC, they need to be tested for radiation tolerance, and tests have been performed using both heavy ions and protons. The ASIC designs were shown to protect against radiation related effects

Measurement of charged-particle multiplicities in gluon and quark jets in p(p)over-bar collisions at root s=1.8 TeV

We report the first largely model independent measurement of charged particle multiplicities in quark and gluon jets, N-q and N-g, produced at the Fermilab Tevatron in p (p) over bar collisions with a center-of-mass energy of 1.8 TeV and recorded by the Collider Detector at Fermilab. The measurements are made for jets with average energies of 41 and 53 GeV by counting charged particle tracks in cones with opening angles of θ(c)=0.28, 0.36, and 0.47 rad around the jet axis. The corresponding jet hardness Q=E-jetθ(c) varies in the range from 12 to 25 GeV. At Q=19.2 GeV, the ratio of multiplicities r=N-g/N-q is found to be 1.64± 0.17, where statistical and systematic uncertainties are added in quadrature. The results are in agreement with resummed perturbative QCD calculations