Skewed parton distributions and F2D at β→1

We show that the diffractive structure function is perturbatively calculable in the domain where the diffractive mass is small but still outside the resonance region. In this domain, which can be characterized by Λ2/Q2⪡1−β⪡Λ2/Q2, the structure function represents a new observable, which is highly sensitive to the small-x skewed gluon distribution. Our leading order calculation and the estimate of next-to-leading order corrections are consistent with available data and demonstrate the potential of more precise data to put further constraints on skewing effects.