Simultaneous extraction of $\alpha_s$ and $m_t$ from LHC $t\bar{t}$ differential distributions

Understand

We present a joint extraction of the strong coupling $\alpha_s$ and the top-quark pole mass $m_t$ from measurements of top-quark pair production performed by the ATLAS and CMS experiments at the 8 TeV LHC.

• For the first time, differential NNLO theory predictions for different values of the top-quark mass are utilised for four kinematic distributions: the average transverse momentum of the top-quark, its average rapidity and the pair invariant mass and rapidity.
• The use of fastNLO tables for these distributions allows rapid evaluation of the differential theory predictions for different PDF sets.
• We consider the single differential distributions from the experiments both separately and in combination in order to obtain the best fit to theory.