Taking the First Steps Toward Higgs and Drell-Yan Production at N4LO in QCD: the Single-real Ingredient

by Adi Suresh (SLAC)

Friday 5 Jun 2026, 12:30 → 14:30 America/Los_Angeles

48/2-224 - Madrone (SLAC)

Since the discovery of the Higgs boson, particle physics has entered a precision era in which theoretical predictions must match the standards accuracy of LHC measurements. Inclusive Higgs-boson production in gluon fusion and Drell–Yan production are central benchmark processes in this effort. While the structure of perturbative QCD corrections is already rich at NLO, each successive order introduces new challenges: additional unresolved radiation, higher-loop amplitudes, more intricate infrared singularities, and novel color structures. Understanding how this complexity evolves is a prerequisite for pushing precision predictions to N4LO.

In this talk, I will present recent progress toward the N4LO inclusive cross sections for gluon-fusion Higgs production and Drell–Yan production. The focus will be on the single-real contributions, involving three QCD partons together with a Higgs boson or a virtual photon. These terms consist of the interference of one-loop and two-loop amplitudes, as well as the interference of tree-level and three-loop amplitudes. The latter is presented in the generalized leading-color limit, which appears to provide a promising approximation for exploring N4LO phenomenology.

These single-real contributions provide more than isolated ingredients for the full N4LO result: they form a laboratory for studying the analytic structures that emerge at this order. Addressing this complexity requires new computational technology capable of organizing and simplifying such structures efficiently. As part of this effort, we introduce CIFAR, a Mathematica package for reducing color factors to general Casimir invariants of simple compact Lie algebras. The calculation therefore serves both as a concrete step toward N4LO phenomenology and as a case study in the computational challenges of extending collider predictions to unprecedented perturbative precision.

SLACTheorySeminar_Adi.pdf