Spin Correlations in Lepton+Jets events with Lorentz-boosted top quarks in pp collisions at √s = 13 TeV

The current LHC data set contains a record number of top quark-antiquark (ttbar) events. This has enabled precision studies of results regarding ttbar production and decay mechanisms predicted by the Standard Model. A well established fact about these ttbar pairs is that they decay weakly before interacting strongly with other quarks and forming hadrons. The decay products of the ttbar pair therefore inherit the spin information that was present in the system at the moment of decay, thus enabling us to observe any spin correlations that were present in the ttbar system via the spins of their decay products. The Standard Model predicts sinusoidal modulations to the azimuthal sum and difference distributions of two decay products. This modulation is a result of interference between different helicity channels. This phenomenon has been studied in the past by CDF at Fermilab and by ATLAS at the LHC but never with the precision afforded by the current LHC data set. We measure these modulations as a function of the boost of the top quark and antiquark using the entire Run 2 CMS dataset of 138fb^-1.