  It is known that there has been classified for all $(-1)$-homogeneous
axisymmetric no-swirl solutions of the three-dimensional Navier-Stokes
equations with a possible singular ray. The main purpose of this paper is to
show that the least singular solutions among such solutions other than Landau
solutions to the Navier-Stokes equations are asymptotically stable under
$L^{3}$-perturbations. Moreover, we establish the $L^{q}$ decay estimate with
an explicit decay rate and a sharp constant for any $q>3$. For that purpose, we
first study the global well-posedness of solutions to the perturbed equations
under small initial data in $L_{\sigma}^{3}$ space and the local well-posedness
with any initial data in $L_{\sigma}^{p}$ spaces for $p\geq3$.
