Hadronic top-quark pair production with NNLL threshold resummation

We compute the total top-quark pair production cross section at the Tevatron and LHC based on approximate NNLO results, and on the summation of threshold logarithms and Coulomb enhancements to all orders with next-to-next-to-leading logarithmic (NNLL) accuracy, including bound-state effects. We findσtt¯(Tevatron)=(7.22−0.47+0.31−0.55+0.71) pb,σtt¯(LHC,s=7 TeV)=(162.6−7.6+7.4−14.7+15.4) pb for mt=173.3 GeVmt=173.3 GeV. The implementation of joint soft and Coulomb resummation, its ambiguities, and the present theoretical uncertainty are discussed in detail. We further obtain new approximate results at N3LO.