Studies of H->bb with ATLAS

Maria Giovanna Foti will use the data collected by the ATLAS detector at Large Hadron Collider (LHC) in Geneva Switzerland for her thesis. ATLAS is large collaborations involving more than 3000 scientists, engineers, and students from hundreds of institutes in about 40 countries. Her thesis will focus on studies of the newly discovered Higgs Boson. The decay of the Higgs boson to bottom quarks is large but it has been measured only at the 3 sigma level due to the poor signal to background ratio in this channel. Maria Giovanna will develop new methods to extract the small H->bb signal from the large QCD background in the ZH final states where the Z boson decays into neutrinos. She will use machine learning tools for classification and regression to improve the reach of the current analysis. She will also include all data collected in run 2 of the LHC. She will especially focus on the study of boosted H->bb decays which are important to study the production cross as at large Higgs boson transverse momentum (Pt). This will lead not only to a better measurement of the H->bb coupling but will also allow the measurement of the Higgs Pt distribution which is sensitive to new physics beyond the standard model. Maria Giovanna will also contribute to the improvement of b-jet tagging by participating in the effort conducted in the ATLAS Common Physics group dedicated to improve the performance of this tool. She will work on the Monte Carlo based extrapolation of the b-tagging efficiency calibration from the ttbar data sample to the high jet pT range, for both calorimeter and track jets. She will adapt the existing code to the latest ATLAS reconstruction software release (release 21) and the new flat-pT Z-prime sample. She will incorporate the tracking CP group recommendations for tracking efficiency, fake rate and impact parameter resolution. She will also study the effects of uncertainties in modelling b and c production and decay properties. The completion of these task will lead to her qualification as an ATLAS author.