Towards a fully massive five-flavour scheme

TL;DR

This paper introduces the five-flavour-massive (5FMS) scheme, a novel approach that retains all quark mass effects in a five-flavour scheme while maintaining resummation properties, and implements it in a Monte Carlo generator.

Contribution

It develops the 5FMS scheme that includes explicit initial state quark mass effects and demonstrates its implementation in SHERPA for scalar particle production.

Findings

The 5FMS scheme retains full quark mass dependence.

Implementation of 5FMS in SHERPA enables accurate simulations.

Comparison shows differences between 5FMS and traditional schemes.

Abstract

In this work we explore first necessary steps to contruct a fully massive version of a variable flavour number scheme. In particular we focus, as an example, on an extension of the five-flavour 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-flavour scheme. We name this scheme five-flavour-massive (5FMS) 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 perfom a comparison of the new scheme with traditional ones for the simple process of scalar particle production in bottom quark fusion.