Observation of Single Top Quark Production in Association with a Z Boson in Proton-Proton Collisions at sqrt[s]=13??TeV.
Observation of Single Top Quark Production in Association with a Z Boson in Proton-Proton Collisions at sqrt[s]=13??TeV. Phys Rev Lett. 2019 Apr 05; 122(13):132003.