The next-to-leading order Higgs impact factor at physical top mass: The real corrections

TL;DR

This paper calculates the real corrections to the impact factor for forward Higgs production, including full top-mass effects, confirming theoretical predictions and consistency with known limits.

Contribution

It provides the first full top-mass dependent calculation of the Higgs impact factor's real corrections at NLO, validating BFKL factorization and IR structure.

Findings

Rapidity divergence matches BFKL predictions

Impact factor vanishes as transverse momentum approaches zero

Infinite-top-mass approximation recovers known results

Abstract

We compute the real corrections to the impact factor for the production of a forward Higgs boson, retaining full top-mass dependence. We demonstrate that the rapidity divergence is the one predicted by the BFKL factorization and perform the explicit subtraction in the BFKL scheme. We show that the IR-structure of the impact factor is the expected one and that, in the infinite-top-mass approximation, the previously known result is recovered. We also verify that the impact factor vanishes when the transverse momenta of the $t$-channel Reggeon goes to zero, in agreement with its gauge-invariant definition, exploiting the $m_t \rightarrow \infty$ expansion up to the next-to-next-to-leading order.