  Based on the assumption of two-quark structure of the scalar $K_0^*(1430)$,
the CP-averaged branching ratios(BRs) and CP-violating asymmetries of charmless
hadronic $B_q(q=u,d,s,c) \to \kst \kstb$ decays are studied in the standard
model(SM) by employing the perturbative QCD(pQCD) factorization approach. Our
predictions are the following: (1) the CP-averaged BRs for $B_{q} \to \kst
\kstb$ decays in both scenarios vary in the range of $10^{-6} \sim 10^{-4}$ in
the SM; (2) the magnitudes of $\acp^{\rm dir}(B_u \to {\kst}^+ {\kstb}^0)$ and
$\acp^{\rm dir}(B_{d,s} \to {\kst}^+ {\kst}^-)$ in Scenario 1 are much larger
than those in Scenario 2 correspondingly; (3) there are no direct CP violations
in $B_{d,s} \to {\kst}^0 {\kstb}^0$ and $B_c \to {\kst}^+ {\kstb}^0$ decays in
the SM because of the pure penguin and tree topology, respectively. A
measurement of our pQCD predictions at the predicted level will favor the
$q\bar q$ structure of the scalar $\kst$ and help us to understand its physical
properties and the involved QCD dynamics.
