Top quark pair production in association with a Z-boson at NLO accuracy

Abstract

We present predictions for the production cross section of t-quark pair production in association with a Z boson at the next-to-leading order (NLO) accuracy using matrix elements obtained from the HELAC-Oneloop package. We use the subtraction method for computing the radiative corrections as implemented in the POWHEG-Box, which was also used in several other computations of similar complexity.

Figures (5)

• Figure 1: Transverse momentum distribution of the $Z$-boson from Ref. Lazopoulos:2008de (LMMP) and from our calculation (PowHel). The lower panel shows our prediction for the NLO $K$-factor compared to that of LMMP.
• Figure 2: Transverse momentum distribution of the t-quark. The lower panel shows our prediction for the NLO $K$-factor compared to a constant value $K_{\rm inc} = 1.39$.
• Figure 3: Transverse momentum distributions of the $Z$-boson (left) and the t-quark (right). The lower panels show our prediction for the NLO $K$-factors compared to the constant value $K_{\rm inc} = 1.39$ found at 14$\,\mathrm{TeV}$ and default scale $\mu_0$.
• Figure 4: Rapidity distributions of the $Z$-boson (left) and the t-quark (right). The lower panels show our prediction for the NLO $K$-factors compared to the constant value $K_{\rm inc} = 1.39$ found at 14$\,\mathrm{TeV}$ and default scale $\mu_0$.
• Figure 5: Distributions of the $R$-separation between the t$\bar{{\rm t}}$-pair (left) and between the t-quark and $Z$-boson (right). The lower panels show our prediction for the NLO $K$-factors compared to the constant value $K_{\rm inc} = 1.39$ found at 14$\,\mathrm{TeV}$ and default scale $\mu_0$.