  We study the sensitivity of the Large Hadron Collider (LHC) to top quark
chromomagnetic (CMDM) and chromoelectric (CEDM) dipole moments and $Wtb$
effective couplings in single-top production in association with a $W^-$ boson,
followed by semileptonic decay of the top. The $Wt$ single-top production mode
helps to isolate the anomalous $ttg$ and $Wtb$ couplings, in contrast to
top-pair production and other single-top production modes, where other
new-physics effects can also contribute. We calculate the top polarization and
the effects of these anomalous couplings on it at two centre-of-mass (cm)
energies, 8 TeV and 14 TeV. As a measure of top polarization, we look at
decay-lepton angular distributions in the laboratory frame, without requiring
reconstruction of the rest frame of the top, and study the effect of the
anomalous couplings on these distributions. We construct certain asymmetries to
study the sensitivity of these distributions to top-quark couplings. We
determine individual limits on the dominant couplings, viz., the real part of
the CMDM $\mathrm{Re}\rho_2$, the imaginary part of the CEDM
$\mathrm{Im}\rho_3$, and the real part of the tensor $Wtb$ coupling
$\mathrm{Ref_{2R}}$, which may be obtained by utilizing these asymmetries at
the LHC. We also obtain simultaneous limits on pairs of these couplings taking
two couplings to be non-zero at a time.
