Towards a complete next-to-logarithmic description of forward exclusive diffractive dijet electroproduction at HERA: Real corrections

Abstract

We studied the $ep\ensuremath{\rightarrow}ep+2\text{ }\mathrm{jets}$ diffractive cross section with ZEUS phase space. Neglecting the $t$-channel momentum in the Born and gluon dipole impact factors, we calculated the corresponding contributions to the cross section differential in $\ensuremath{\beta}=\frac{{Q}^{2}}{{Q}^{2}+{M}_{2\text{ }\mathrm{jets}}^{2}}$ and the angle $\ensuremath{\phi}$ between the leptonic and hadronic planes. The gluon dipole contribution was obtained in the exclusive ${k}_{t}$-algorithm with the exclusive cut ${y}_{\mathrm{cut}}=0.15$ in the small ${y}_{\mathrm{cut}}$ approximation. In the collinear approximation we canceled singularities between real and virtual contributions to the $q\overline{q}$ dipole configuration, keeping the exact ${y}_{\mathrm{cut}}$ dependency. We used the Golec-Biernat--W\"usthoff (GBW) parametrization for the dipole matrix element and linearized the double dipole contributions. The results give roughly $\frac{1}{2}$ of the observed cross section for small $\ensuremath{\beta}$ and coincide with it for large $\ensuremath{\beta}$.