Solution of $a_2\mathrm{/}{a}_1$ sign problem in heavy meson decays: nonfactorizable soft gluons in nonleptonic heavy meson decays

For the first time, a solution to the $a_2\mathrm{/}{a}_1$ sign problem in heavy meson decay based on PQCD factorization theorems. The point is to include QCD evolution effort characteristic scales involved in decay processes.