Abstract
We present the computation of the differential cross section for the process p p(\( \overline{p} \)) → (W+ W− b \( \overline{\mathrm{b}} \) →) e+ ν e μ − \( \overline{\nu} \) μ b \( \overline{\mathrm{b}} \) + X at NLO QCD accuracy matched to Shower Monte Carlo (SMC) simulations using PowHel, on the basis of the interface between HELAC-NLO and POWHEG-BOX. We include all resonant and non-resonant contributions. This is achieved by fully taking into account the effect of off-shell t-quarks and off-shell W-bosons in the complex mass scheme. We also present a program called DECAYER that can be used to let the t-quarks present in the event files for p p(\( \overline{p} \)) → t \( \overline{\mathrm{t}} \) X processes decay including both the finite width of the t-quarks and spin correlations. We present predictions for both the Tevatron and the LHC, with emphasis on differences emerging from three different W+ W− b \( \overline{\mathrm{b}} \) hadroproduction computations: (i) full implementation of the p p(\( \overline{p} \)) → W+ W− b \( \overline{\mathrm{b}} \) process, (ii) generating on-shell t-quarks pushed off-shell with a Breit-Wigner finite width and decayed by Decayer, and (iii) on-shell t-quark production followed by decay in the narrow width approximation, as described by the SMC.
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Garzelli, M.V., Kardos, A. & Trócsányi, Z. Hadroproduction of W+ W− b \( \overline{\mathrm{b}} \) at NLO accuracy matched with shower Monte Carlo programs. J. High Energ. Phys. 2014, 69 (2014). https://doi.org/10.1007/JHEP08(2014)069
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DOI: https://doi.org/10.1007/JHEP08(2014)069