Top Quark Modeling and Generators in CMS

Abstract: Recent top quark event modeling studies done using LHC proton-proton collision data collected with the CMS detector at centre of mass energies of 8 and 13 TeV and state-of-the-art theoretical predictions are summarized. A new factorized approach for parton shower uncertainties is presented. A top quark specific PYTHIA8 CMS tune, along with tunes using new color reconnection models, is discussed. The possibility of having a consistent choice of parton distribution function in the matrix element and the parton shower is demonstrated with tunes constructed with leading, next-to-leading, and next-to-next-to-leading order versions of NNPDF3.1 set compared to minimum bias and underlying event data.