Threshold resummation for the production of four top quarks at the LHC

We compute the total cross section for $t\bar{t}t\bar{t}$ production at next-to-leading logarithmic (NLL${}^{\mathrm{\prime }}$) accuracy. This is the first time resummation is performed for a hadron-collider process with four colored particles in the final state. The calculation is matched to the next-to-leading order strong and electroweak corrections. The NLL${}^{\mathrm{\prime }}$ corrections enhance the total production rate by 26%. The size of the theoretical error due to scale variation is reduced by close to a factor of two, bringing the theoretical error significantly below the current experimental uncertainty of the measurement.