Precursor of Color Superconductivity

We investigate possible precursory phenomena of color superconductivity at finite temperature $T$ with an effective theory of QCD. It is found that the fluctuation of the diquark pair field exists with a prominent strength even well above the critical temperature $T_c$. We show that such a fluctuaiton forms a collective mode, the corresponding pole of which approaches the origin as $T$ is lowered to $T_c$ in the complex energy plane. We discuss the possible relevance of the precursor to the observables to be detected in heavy-ion collisions.