QCD corrections to Associated t-tbar-H production at the Tevatron

TL;DR

This work delivers a complete next-to-leading order QCD calculation for associated tt̄h production at the Tevatron, focusing on the qq̄ initial state and incorporating both virtual corrections (including UV/IR structures and pentagon diagrams) and real gluon emission via phase-space slicing. By employing two complementary PSS approaches (two-cutoff and one-cutoff) and performing detailed mass factorization into MSbar PDFs, the authors achieve a finite, renormalization-scale–stable prediction for σ_NLO at √s_H = 2 TeV. The numerical results show a substantial reduction in scale dependence and reveal modest to moderate K-factors depending on the scale choice, with σ_NLO in the 1–5 fb range for Higgs masses between 120 and 180 GeV, along with an overall ~12% theoretical uncertainty. The methodology, including handling of pentagon integrals and cross-checks between PSS schemes, provides a robust framework for NLO studies of similar multi-particle final states in hadronic collisions.

Abstract

We present in detail the calculation of the O(alpha_s^3)inclusive total cross section for the process (p pbar-> t tbar h) in the Standard Model, at the Tevatron center-of-mass energy sqrt(s_H)=2 TeV. The next-to-leading order QCD corrections significantly reduce the renormalization and factorization scale dependence of the Born cross section. They slightly decrease or increase the Born cross section depending on the values of the renormalization and factorization scales

Figures (13)

• Figure 1: Feynman diagrams contributing to the lowest order process, $q\bar{q}\rightarrow t\bar{t}h$. The arrows indicate the momentum flow.
• Figure 2: ${\cal O}(\alpha_s)$ virtual corrections: self-energy diagrams $S_1^{(1,2)}$ and $S_2^{(1,2)}$.
• Figure 3: ${\cal O}(\alpha_s)$ virtual corrections: vertex diagrams $V_1^{(1,2)}$-$V_6^{(1,2)}$.
• Figure 4: ${\cal O}(\alpha_s)$ virtual corrections: box diagrams $B_1$, $B_2^{(1,2)}$ and $B_3^{(1-4)}$.
• Figure 5: ${\cal O}(\alpha_s)$ virtual corrections: pentagon diagrams $P_1$ and $P_2$.