INFN, Sezione di Firenze and Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, 50019 Sesto Fiorentino, Firenze, Italy.
Dipartimento di Fisica, Università degli Studi di Milano and INFN, Sezione di Milano, 20133 Milano, Italy.
Phys Rev Lett. 2023 Mar 17;130(11):111902. doi: 10.1103/PhysRevLett.130.111902.
The associated production of a Higgs boson with a top-antitop quark pair is a crucial process at the LHC since it allows for a direct measurement of the top-quark Yukawa coupling. We present the computation of the radiative corrections to this process at the next-to-next-to-leading order (NNLO) in QCD perturbation theory. This is the very first computation for a 2→3 process with massive colored particles at this perturbative order. We develop a soft Higgs boson approximation for loop amplitudes, which enables us to reliably quantify the impact of the yet unknown two-loop contribution. At the center-of-mass energy sqrt[s]=13 TeV, the NNLO corrections increase the next-to-leading order result for the total cross section by about 4% and lead to a significant reduction of perturbative uncertainties.
希格斯玻色子与顶反顶夸克对的关联产生是 LHC 中的一个关键过程，因为它允许直接测量顶夸克 Yukawa 耦合。我们在 QCD 微扰理论的次领头阶（NNLO）下展示了对该过程的辐射修正的计算。这是在这个微扰阶次上对具有大量有色粒子的 2→3 过程的首次计算。我们为环振幅开发了软希格斯玻色子近似，这使我们能够可靠地量化未知的两环贡献的影响。在质心能量 sqrt[s]=13 TeV 下，NNLO 修正将次领头阶的总截面结果增加了约 4%，并导致了微扰不确定性的显著降低。
