Towards a fully massive five-flavor scheme

In this paper, we explore first necessary steps to construct a fully massive version of a variable-flavor number scheme. In particular we focus, as an example, on an extension of the five-flavor scheme, where instead of neglecting explicit initial state quark mass effects, we retain all massive dependence, while keeping the resummation properties of the massless five-flavor scheme. We name this scheme the five-flavor-massive scheme. Apart from consistently modified parton distribution functions, we provide all the ingredients that are needed to implement this scheme at MC@NLO accuracy, in a Monte Carlo event generator. As proof of concept we implement this scheme in sherpa and perform a comparison of the new scheme with traditional ones for the simple process of scalar particle production in bottom-quark fusion.