Speaker
Description
I will present a new formalism for constructing integrand-level finite representations of scattering amplitudes. The central ingredient is an exact graphical decomposition of gluon propagation into physical (G) and unphysical (K) polarizations. Applied directly to Feynman graphs, the (G)-(K) decomposition generates exact identities at the level of Feynman integrals, without making soft or collinear approximations. Up to two loops, it reorganizes each amplitude into a sum of locally finite integrals and a remaining infrared-divergent integral depending on a single scale. Ward-identity cancellations are performed analytically at the integrand level, so no local counterterms are required. In particular, the construction avoids the momentum-shift counterterms that arise in other approaches to local infrared factorization and does not rely on a special choice of loop-momentum routing. I will illustrate the formalism for
$$ q+g\to q+mH $$
and its crossed channels, where the graphical decomposition can be carried out explicitly for arbitrary Higgs multiplicity.