Dominant QCD Backgrounds in Higgs Boson Analyses at the LHC: A Study of $pp\to t\overline{t}+2$ Jets at Next-to-Leading Order

We report the results of a next-to-leading order simulation of top quark pair production in association with two jets. With our inclusive cuts, we show that the corrections with respect to leading order are negative and small, reaching 11%. The error obtained by scale variation is of the same order. Additionally, we reproduce the result of a previous study of top quark pair production in association with a single jet.

Figure 1

Example diagrams contributing to the signal $t\overline{t}{H}^{*}\to t\overline{t}b\overline{b}$, and the irreducible background with the same final state, as well as the reducible background with two jets. Thick blue lines correspond to top quarks, the wiggly to gluons as usual.

Figure 2

Scale dependence of the total cross section for $pp\to t\overline{t}jj+X$ at the LHC with ${\mu }_R={\mu }_F=\xi {\mu }_0$ where ${\mu }_0=m_t$. The blue dotted curve corresponds to the LO, the red solid to the NLO result, whereas the green dashed to the NLO result with a jet veto of 50 GeV.

Figure 3

Distribution of the invariant mass $m_{jj}$ of the first and the second hardest jet for $pp\to t\overline{t}jj+X$ at the LHC. The red solid line refers to the NLO result, while the blue dotted line to the LO one.

Figure 4

Distribution in the transverse momentum $p_{T_j}$ of the first hardest jet for $pp\to t\overline{t}jj+X$ at the LHC. The red solid line refers to the NLO result, while the blue dotted line to the LO one.

Figure 5

Distribution in the transverse momentum $p_{T_j}$ of the second hardest jet for $pp\to t\overline{t}jj+X$ at the LHC. The red solid line refers to the NLO result, while the blue dotted line to the LO one.