  The critical behavior of three-dimensional weakly diluted quenched Ising
model is examined on the base of six-loop renormalization group expansions
obtained within the minimal subtraction scheme in $4-\epsilon$ space
dimensions. For this purpose the $\phi^4$ field theory with cubic symmetry was
analyzed in the replica limit $n\rightarrow 0$. Along with renormalization
group expansions in terms of renormalized couplings the $\sqrt{\varepsilon}$
expansions of critical exponents are presented. Corresponding numerical
estimates for the physical, three-dimensional system are obtained by means of
different resummation procedures applied both to the $\sqrt{\varepsilon}$
series and to initial renormalization group expansions. The results given by
the latter approach are in a good agreement with their counterparts obtained
experimentally and within the Monte Carlo simulations, while resumming of
$\sqrt{\varepsilon}$ series themselves turned out to be disappointing.
