Higgs Radiation off Top Quarks at the Tevatron and the LHC

TL;DR

The QCD corrections to these processes in the standard model at next-to-leading order reduce the renormalization and factorization scale dependence considerably and stabilize the theoretical predictions for the cross sections.

Abstract

Higgs bosons can be searched for in the channels $p\bar p/pp\to t\bar tH+X$ at the Tevatron and the LHC. We have calculated the QCD corrections to these processes in the Standard Model at next-to-leading order. The higher-order corrections reduce the renormalization and factorization scale dependence considerably and stabilize the theoretical predictions for the cross sections. At the central scale $μ=(2m_t+M_H)/2$ the properly defined $K$ factors are slightly below unity for the Tevatron ($K \sim 0.8$) and slightly above unity for the LHC ($K \sim 1.2$).

Figures (3)

• Figure 1: A generic set of diagrams (a) for the Born level, (b) for virtual gluon exchange, (c) gluon radiation and (d) parton splitting in the subprocesses $q\bar{q}, gg\to t\bar{t}H$ etc.
• Figure 2: (a) The cross section for $p\bar{p}\to t\bar{t}H\;+\;X$ at the Tevatron in LO and NLO approximation, with the renormalization and factorization scales set to $\mu=m_t+M_H/2$; (b) variation of the cross section with the renormalization and factorization scales for a fixed Higgs-boson mass $M_H=120\,\mathrm{GeV}$.
• Figure 3: Analysis of $pp\to t\bar{t}H\;+\;X$ at the LHC; (a) production cross section, and (b) renormalization/factorization-scale dependence (parameters as specified in the previous figure).