Weak interaction corrections to hadronic top quark pair production: contributions from quark-gluon and $b \bar b$ induced reactions

As an addendum to our previous evaluation of the weak-interaction corrections to hadronic top-quark pair production we determine the leading weak-interaction contributions due to the subprocesses $b {\bar b} \to t {\bar t}$ and $g q ({\bar q}) \to t {\bar t} q ({\bar q})$. For several distributions in $t {\bar t}$ production at the LHC we find that these contributions are non-negligible as compared to the weak corrections from the other partonic subprocesses.