  We study single production of exotic vectorlike $Y$ quark with electric
charge $|Q_{Y}|=4/3$ and its subsequent decay at the High Luminosity LHC
(HL-LHC). Most of the vector like quark (VLQ) decays have the electroweak $W$
bosons in the intermediate state. Besides their direct productions singly or
pairs, the $W$-bosons are involved in decay chains as a result of the decay of
a top quark which contributes to the background. This is particularly the case
since vectorlike $Y$ quark, which is estimated to be produced with a high
cross-section, can only decay via a $W$ boson and a down type quark ($d,s,b$).
We calculate the cross sections of signal (for different couplings and mass
values) and relevant Standard Model (SM) backgrounds. After a fast simulation
of signal and background events, estimations of the sensitivity to the
parameters (mass range 1000-2500 GeV for coupling value $\kappa_{Y}=0.5$, and
mass range 500-2000 GeV for coupling values $\kappa_{Y}=0.3$ and
$\kappa_{Y}=0.15$) have been presented at the HL-LHC with center of mass energy
$\sqrt{s}=14$ TeV and integrated luminosity projections of 300 fb$^{-1}$, 1000
fb$^{-1}$ and 3000 fb$^{-1}$.
