Unintegrated gluon distributions from the color dipole cross section in the BGK saturation model

Abstract

We evaluate the unintegrated gluon distribution of the proton starting from a parametrization of the color dipole cross section including Dokshitzer–Gribov–Lipatov–Altarelli–Parisi (DGLAP) evolution and saturation effects. To this end, we perform the Fourier-Bessel transform of σ(x,r)/α(r). At large transverse momentum of gluons we match the so-obtained distribution to the logarithmic derivative of the collinear gluon distribution. We check our approach by calculating the proton structure function FL(x,Q2) finding good agreement with HERA data.