Evidence for the higher twists effects in diffractive DIS at HERA

We study a twist decomposition of diffractive structure functions in the diffractive deep inelastic scattering at HERA. At low $Q^2$ and at large energy the data exhibit a strong deviation from the twist-2 NLO DGLAP description. It is found that this deviation in consistent with higher twist effects. We conclude that the DDIS at HERA provides the first, strong evidence of higher twist effects in DIS.