Search for a new pseudoscalar decaying into a pair of bottom and antibottom quarks in top-associated production in s=13 TeV proton–proton collisions with the ATLAS detector

A search for a pseudoscalar a produced in association with a top-quark pair, or in association with a single top quark plus a W boson, with the pseudoscalar decaying into b-quarks (a -> b (b) over bar), is performed using the full Run 2 data sample using