Speaker
Description
Splitting functions are the factorized forms of collinear dynamics in perturbative QCD and are central ingredients in parton shower models, whose precision is crucial for finding and understanding new physics in collider events. We present a compact form of the massive 1→3 tree-level QCD splitting functions, obtained without reference to soft or quasi-collinear limits. The triple-collinear kernels are computed by layering scalar (semi-classical) interaction and fermionic interference terms, yielding a decomposition in terms of lower-order expressions, scalar dipole antenna functions, and pure higher-order remainders. The two-gluon radiator functions arising in this context are novel and generalize expressions previously obtained from the double-soft approximation. We compare against existing massive and massless results, and discuss how this decomposition enables systematic integration of the 1→3 splittings into current Monte-Carlo simulations, extending the precision of parton shower calculations.