Differential Higgs Boson Pair Production at Next-to-Next-to-Leading Order in QCD (1606.09519v1)

Abstract: We report on the first fully differential calculation for double Higgs boson production through gluon fusion in hadron collisions up to next-to-next-to-leading order (NNLO) in QCD perturbation theory. The calculation is performed in the heavy-top limit of the Standard Model, and in the phenomenological results we focus on pp collisions at 14 TeV. We present differential distributions through NNLO for various observables including the transverse-momentum and rapidity distributions of the two Higgs bosons. NNLO corrections are at the level of 10%-25% with respect to the next-to-leading order (NLO) prediction with a residual scale uncertainty of 5%-15% and an overall mild phase-space dependence. Only at NNLO the perturbative expansion starts to converge yielding overlapping scale uncertainty bands between NNLO and NLO in most of the phase-space. The calculation includes NLO predictions for pp -> HH+jet+X. Corrections to the corresponding distributions exceed 50% with a residual scale dependence of 20%-30%.

Differential Higgs Boson Pair Production at Next-to-Next-to-Leading Order

The presented paper details an advanced paper on the fully differential calculation of Higgs boson pair production via gluon fusion through next-to-next-to-leading order (NNLO) in QCD perturbation theory. This research provides a significant step forward in our understanding of Higgs boson pair production, operating within the heavy-top limit of the Standard Model. The analysis focuses on proton-proton ($pp$) collisions at a center-of-mass energy of 14 TeV.

The authors report differential distributions through NNLO for various observables, particularly the transverse momentum and rapidity of the Higgs bosons. This calculation shows NNLO corrections at a magnitude of approximately 10%-25% relative to the next-to-leading order (NLO) predictions, demonstrating a mild dependence on phase space. As expected at such high perturbative orders, the residual scale uncertainty is reduced to 5%-15%, highlighting the enhanced precision of NNLO calculations over NLO.

Essentially, the perturbative expansion shows convergence only at NNLO, with overlapping scale uncertainty bands between NNLO and NLO in most phase-space regions, marking a pivotal improvement in perturbative QCD modeling. The calculation additionally delivers NLO predictions for $pp$ processes while noting the corrections to distributions exceeding 50%, alongside a residual scale dependence ranging from 20%-30%.

The paper details the employment of the $$ subtraction formalism combined with the Monte Carlo framework, supplemented by tree and one-loop amplitudes from the OpenLoops generator. This methodological approach is both robust and flexible, promising precise theoretical predictions essential for experimental analysis.

In practice, the results present key insights into the cross-section predictions for Higgs boson pair production, crucial for testing electroweak symmetry breaking and probing potential new physics beyond the Standard Model. The authors judiciously limit the paper to the heavy-top quark limit, suggesting future work would benefit from integrating exact NLO virtual contributions with NNLO heavy-top calculations for higher accuracy.

Looking ahead, the amalgamation of precise amplitude calculations with decay processes could dramatically enhance phenomenological insight, making this research invaluable for the deeper investigations into the Higgs mechanism and its associated couplings. This paper intricately positions itself as an indispensable resource for the traditionally challenging experimental measurements of Higgs boson pair productions, driving forward theoretical predictions foundational in probing the Higgs sector.