Speaker
Description
We present complete next-to-leading-order predictions for off-shell $t\bar{t}W^+$ production in the two-lepton same-sign channel at the LHC, considering the process
$pp\to \mu^+\nu_\mu\,e^+\nu_e\,b\bar{b}\,jj+X$
at a centre-of-mass energy of $\sqrt{s}=13.6~\mathrm{TeV}$. Finite-width effects of the top quarks and massive electroweak bosons are treated consistently, while doubly-resonant, singly-resonant and non-resonant contributions, together with all interference effects, are retained. The calculation incorporates the full set of Born contributions, ranging from $\mathcal{O}(\alpha_s^4\alpha^4)$ to $\mathcal{O}(\alpha^8)$, as well as all corresponding NLO QCD and electroweak corrections. This constitutes the first full off-shell NLO QCD calculation for the $2\ell\mathrm{SS}$ channel and, more generally, the first complete NLO prediction for this process. Results are presented for integrated and differential fiducial cross sections. Particular emphasis is placed on the impact of formally subleading perturbative contributions, which are found to induce sizeable effects in the integrated cross-sections and differential distributions. Their size, kinematic dependence and sensitivity to the adopted fiducial selection are investigated within the complete off-shell description of the process.