  In this paper, we study the discovery potential of a Vector-Like $B$ quark
(VLB) via the process $pp \to B(\to bZ)j\to b(Z \to \nu_l\bar{\nu_l})j$ at the
Large Hadron Collider (LHC) with $\sqrt{s}=14$ TeV. In the framework of a
simplified model, we perform a scan over its parameter space and test its
viability following a Monte Carlo analysis developed to include all production
and decay dynamics. We use cut-and-count combined with Extreme Gradient
Boosting (XGBoost) methods to classify the signal and background events in
order to improve the efficiency of signal identification and background
rejection. We find that this approach can reduce background events
significantly while the signal retention rate is much higher than that of
traditional methods, thereby improving the VLB discovery potential. We then
calculate the exclusion and discovery capabilities for VLBs and find that the
advantages of the cut-and-count plus XGBoost method especially lie in the
high-mass region, i.e., $m_B > 1500 \text{ GeV}$. We finally obtain the
following LHC results in terms of the coupling and chiral structure of a
singlet heavy VLB interactions: (i) for $g^{\ast}$=0.2 and $R_L=0$ with 3000
fb$^{-1}$, the $B$ quark mass can be be excluded (discovered) up to 3000 GeV
(2500 GeV); (ii) for $g^{\ast}$=0.2 and $R_L=0.5$ with 3000 fb$^{-1}$, the
exclusion (discovery) region can reach up to 4750 GeV (4250 GeV).
