B1b: Precision top-quark physics at the LHC

The top quark is the heaviest elementary particle in the Standard Model (SM). It is unique among the fermions and its potential to provide insights into physics beyond the SM is anticipated. In view of ongoing searches for new physics at the LHC, where the emphasis is on looking for small deviations from the SM predictions, state of the art theoretical results for the top quark are indispensable. The purpose of this project is to provide the most precise theoretical predictions for fully realistic final states in tt ̄ and tt ̄ + X production, where X=γ,Z,W ,H,tt.Our results will be employed to study broad phenomenological aspectof top quark physics at the LHC, from SM parameter extraction to constraining new physics.

1. NLO: Full QCD + Electroweak Effects: state of the art theoretical predictions for $ pp \to t \bar t + X$ (lepton-plus-jets), state of the art theoretical predictions for $pp \to t \bar t t \bar t$ (dileptons); long-term goal (calculation of electroweak corrections to $t \bar t + X$;
2. Dimension-6 Gauge Invariant Effective Operators in Top Quark Physics: minimal set of anomalous couplings for $W-t-b$ $t \bar t X$, $X = \gamma, Z, H$; sensitivity to top quark anomalous couplings in the $pp \to t \bar t + X$;
3. NNLO QCD: production+decays in the narrow width approximation: fiducial $t \bar t$ cross sections, (dileptons). Gluon PDF determination; very precise $m_t$ extraction from (differential) leptonic observables;
4. Long term goal: differential predictions for $pp \to t \bar t \gamma$, $pp \to t \bar t H$.