NNLO B-fragmentation fits and their application to $t\bar t$ production and decay at the LHC

TL;DR

This paper derives NNLO accurate non-perturbative fragmentation functions for B-hadrons, J/psi, and muons from B decays, and applies them to improve predictions of top quark pair production and decay at the LHC, especially for top mass-sensitive observables.

Contribution

It provides the first set of NNLO fragmentation functions with uncertainties for B-hadrons, J/psi, and muons, fully consistent with NNLO calculations for specific final states.

Findings

Fragmentation functions are accurate at NNLO with uncertainties.

Applied functions improve predictions for t-tbar events at the LHC.

Enhanced analysis of top quark mass-sensitive observables.

Abstract

In this work we derive three sets of non-perturbative fragmentation functions, with uncertainties, for $B$-hadrons, $J/\psi$'s and muons resulting from semileptonic $B$ decays. All three sets are with next-to-next-to leading order accuracy and include next-to-next-to leading logarithmic soft gluon resummation. The novel feature of these new sets is that they are fully consistent with our formalism for next-to-next-to leading order (NNLO) calculations for final states with identified $B$, $J/\psi$ or a $\mu$. We employ the fragmentation functions derived in this work to make state of the art predictions for such final states in $t\bar t$ events at the LHC. A special emphasis is placed on observables sensitive to the top quark mass. The present work opens the door for many LHC applications, like, open $B$ production or $B$ production in association with bosons.