Multigluonic scattering amplitudes of heavy quarks

TL;DR

This paper develops a Berends–Giele based, helicity formalism approach to compute tree-level multigluon amplitudes involving a heavy quark pair. By constructing off-shell spinorial currents for massive fermions and implementing recursion relations, the authors obtain on-shell amplitudes and the quark–antiquark vector current for arbitrary numbers of positive-helicity gluons, along with explicit low-multiplicity examples. A key result is that in the heavy top quark effective theory the holomorphic part of Higgs to qqbar plus gluons amplitudes vanishes for helicity conserving configurations, illustrating a mass-dependent cancellation. The work provides compact, efficient expressions that complement MHV methods and enhance predictive power for heavy quark production and Higgs processes at high-energy colliders.

Abstract

We consider heavy quark and antiquark off-shell spinorial currents with emission of an arbitrary number of gluons of positive helicity. From this results we calculate the corresponding on-shell scattering amplitude and the quark-antiquark vector current. Then, we show that in the heavy top quark effective theory the holomorfic component of the Higgs $\to q \bar{q} + n$-gluon amplitude vanish for helicity conserving configurations.