NLO Higgs boson rapidity distribution at hadron colliders
Charalampos Anastasiou, Lance Dixon, Kirill Melnikov
TL;DR
This paper develops and applies an extended unitarity cutting method to compute NLO rapidity distributions for CP-even and CP-odd Higgs bosons produced in hadron collisions via gluon fusion in the heavy-top limit. By mapping the rapidity constraint to an effective propagator, the authors reduce constrained phase-space integrals to loop integrals and obtain analytic partonic distributions across all relevant channels, with explicit cancellation of $oldsymbol{ ext{epsilon}}$-poles after renormalization and mass factorization. Numerical results show that NLO corrections to the normalized rapidity distribution are small (about 5% at zero rapidity for the LHC) and exhibit reduced scale dependence, indicating a stable distribution shape suitable for LO Monte Carlo normalization to NNLO total cross sections. The approach also provides a path toward NNLO differential distributions and can be extended to other processes such as Drell–Yan.
Abstract
We describe a new method, based on an extension of the unitarity cutting rules proposed earlier, which is very efficient for the algorithmic evaluation of phase-space integrals for various differential distributions. As a first application, we compute the next-to-leading order normalized rapidity distribution of the CP-even and the CP-odd Higgs boson produced in hadron collisions through gluon fusion. We work in the heavy top-quark approximation; we find that the NLO corrections at the LHC are approximately 5% in the zero rapidity region.