Diffractive Open Charm Production in Deep-Inelastic Scattering and Photoproduction at HERA

摘要

Measurements are presented of diffractive open charm production at HERA. Theevent topology is given by ep -> eX Y where the system X contains at least onecharmed hadron and is well separated by a large rapidity gap from a leadinglow-mass proton remnant system Y. Two analysis techniques are used for thecross section measurements. In the first, the charm quark is tagged by thereconstruction of a D*(2010) meson. This technique is used in deep-inelasticscattering (DIS) and photoproduction. In the second, a method based on thedisplacement of tracks from the primary vertex is used to measure the opencharm contribution to the inclusive diffractive cross section in DIS. Themeasurements are compared with next-to-leading order QCD predictions based ondiffractive parton density functions previously obtained from a QCD analysis ofthe inclusive diffractive cross section at H1. A good agreement is observed inthe full kinematic regime, which supports the validity of QCD factorization foropen charm production in diffractive DIS and photoproduction.