Aula Caldirola (University of Milan Statale)
Speakers: Stephen Jones (Durham University)
An important goal of the High-Luminosity run of the LHC is the measurement of the Higgs boson pair production cross-section, thereby placing constraints on the Higgs boson self-couplings. The latest European Strategy for Particle Physics update indicates that, under fairly conservative assumptions, the HL-LHC is expected to discover this process, motivating a detailed study. Theoretically, this process is known to N3LO in the Heavy Top-quark Limit (HTL), and NLO QCD and NLO EW corrections are known when quark masses are included. The dominant remaining theoretical uncertainties come from the dependence of the prediction on the top-quark mass scheme and scale. In this talk, we discuss an attempt to understand the structure of these mass corrections. The Method of Regions and the tools of Soft-Collinear Effective Theory (SCET) are used to understand the structure of the quark-mass corrections in the gg -> HH virtual amplitude in the high-energy limit, defined by s,|t|,|u| >> mT^2 >> mH^2. We argue that the mass corrections follow a predictable factorised pattern at leading power. An ongoing effort to compute the leading small top-mass behaviour at NNLO QCD (3-loops) is presented.