Electroweak t$\overline{t}$ hadroproduction in the presence of heavy Z′ and W′ bosons at NLO QCD in POWHEG

We present a new calculation of next-to-leading order QCD corrections to electroweak top-quark pair hadroproduction in extensions of the Standard Model (SM) with extra heavy neutral and charged spin-1 resonances which considerably extends and improves an earlier calculation performed by some of us. In particular, we allow for flavor-non-diagonal Z′ couplings and take into account nonresonant production in the SM and beyond including the contributions with $\overline{t}$-channel W and W′ bosons. As a result, models with a more complicated flavor structure which have been proposed to explain the flavor anomalies in B decays can now be accommodated in our code. Moreover, the new $\overline{t}$-channel contributions lead to improved cross sections predictions at higher energies beyond the LHC reach. All amplitudes are generated using the recola2 package. As in our previous work, we include next-to-leading order QCD corrections and consistently match to parton showers with the POWHEG method fully taking into account the interference effects between the SM and new physics amplitudes. We consider the sequential Standard Model, the topcolor model, as well as the third family hypercharge model featuring non-flavor-diagonal Z′ couplings and present numerical results for t$\overline{t}$ cross sections at hadron colliders with a center-of-mass energy up to 100 TeV.