Towards Quarkonium Fragmentation from NRQCD in a Variable-Flavor Number Scheme

Abstract

We address quarkonium formation at moderate to large transverse momenta, where the single-parton collinear fragmentation prevails over the short-distance emission, directly from the hard sub-scattering, of the constituent heavy-quark pair. We rely on Non-Relativistic-QCD (NRQCD) Next-to-Leading Order (NLO) calculations for all parton fragmentation channels to quarkonia, taken as proxies for initial-scale inputs. Preliminary sets of Variable-Flavor Number-Scheme (VFNS) fragmentation functions (FFs) are built via a DGLAP scheme that properly accounts for evolution thresholds. Statistical errors are assessed via a Monte Carlo (MC), replica-like approach aimed at catching Missing Higher-Order Uncertainties (MHOUs).