D*+- meson production in deep inelastic diffractive interactions at HERA

Abstract A measurement is presented of the cross section for D ∗± meson production in diffractive deep-inelastic scattering for the first time at HERA. The cross section is given for the process ep → eXY , where the system  X contains at least one D ∗± meson and is separated by a large rapidity gap from a low mass proton remnant system  Y . The cross section is presented in the diffractive deep-inelastic region defined by 2 Q 2 2 , 0.05 y x P , M Y t | 2 . The D ∗± mesons are restricted to the range p T,D ∗ >2  GeV and |η D ∗ | . The cross section is found to be 246±54±56 pb and forms about 6% of the corresponding inclusive D ∗± cross section. The cross section is presented as a function of various kinematic variables, including z P obs which is an estimate of the fraction of the momentum of the diffractive exchange carried by the parton entering the hard-subprocess. The data show a large component of the cross section at low z P obs where the contribution of the boson–gluon-fusion process is expected to dominate. The data are compared with several QCD-based calculations.