Impact of colored scalars on D0-D¯0 mixing in diquark models

Inspired by the recent observation of the D0-D¯0 mixing, we explore the effects of colored scalars on the ΔC=2 process in diquark models. As an illustration, we investigate the diquarks with the quantum numbers of (6,1,1/3) and (6,1,4/3) under SU(3)C×SU(2)L×U(1)Y gauge symmetries, which contribute to the process at one-loop and tree levels, respectively. We show that ΔmD gives the strongest constraint on the free parameters. In addition, we find that the small couplings can be naturally interpreted by the suppressed flavor mixings if the diquark of (6,1,4/3) only couples to the third generation.