Renormalization Group Improved Small-x Equation1

We propose and analyze an improved small-x equation which incorporates exact leading and next-to-leading BFKL kernels on one hand and renormalization group constraints in the relevant collinear limits on the other. We work out in detail the recently proposed ω-expansion of the solution, derive the Green’s function factorization properties and discuss both the gluon anomalous dimension and the hard pomeron. The resummed results are stable, nearly renormalization-scheme independent, and join smoothly with the fixed order perturbative regime. Two critical hard pomeron exponents ωc(Q) and ωs(Q) are provided, which — for reasonable strong-coupling extrapolations — are argued to provide bounds on the pomeron intercept ωP.