  The possibility of a vectorlike top partner decaying to a new colourless
weak-singlet scalar or pseudoscalar has attracted some attention in the
literature. We investigate the production of a weak-singlet charge-$2/3$ $T$
quark that can decay to a spinless boson ($\Phi$) and a top quark at the LHC.
Earlier, in 2203.13753, we have shown that in a large part of the parameter
space, the $T\to t\Phi$ and the loop-induced $\Phi \to gg$ decays become the
dominant decay modes for these particles. Here, we investigate the discovery
prospects of the $T$ quark in this region through the above decays. In
particular, we focus on the $pp\to TT\to (t\Phi)(t\Phi)\to (t(gg))\,(t(gg))$
channel. Separating this signal from the huge Standard Model background is a
challenging task, forcing us to employ a multivariate machine-learning
technique. We find that the above channel can be a discovery channel of the top
partner in the large part of the parameter space where the above decay chain
dominates. Our analysis is largely model-independent, and hence our results
would be useful in a broad class of new physics models.
