Diffractive Jet-Production in Deep-Inelastic ep Collisions at HERA

Reference Frank-Peter Schilling, talk presented at DIS 2000; M Martinez, talk presented at ICHEP 2000, April 2000
Document Conference paper
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Contact Frank-Peter Schilling
Abstract A measurement is presented of dijet and 3-jet cross sections in low-$|t|$ diffractive deep-inelastic scattering interactions of the type $ep ightarrow eXY$, where the photon dissociation system $X$ is separated by a large rapidity gap from a leading low-mass baryonic system $Y$. Data taken in 1996 to 1997 with the H1 detector at HERA, corresponding to an integrated luminosity of $18.0 m\ pb^{-1}$, are used to measure a comprehensive set of single and double differential cross sections in the kinematic range $44 m\ GeV$. The nature of the energy flow not attributed to the dijet system is also investigated. Viewed in terms of the diffractive scattering of parton fluctuations of the photon, the data require the dominance of $q\overline{q}g$ over $q\overline{q}$ states. They constrain the diffractive gluon distribution and require a large fraction of the colorless exchange momentum to be carried by gluons. The data are consistent with factorization of the $x_\pom$ dependence, a Pomeron intercept value of $lpha_\pom(0)=1.2$ and a sizeable fraction of events where the virtual photon is resolved. Soft color neutralization models can reproduce the shapes of the differential distributions but underestimate the cross section. A perturbative QCD calculation based on 2-gluon exchange is in agreement with the data at low $x_\pom$ values. The 3-jet cross sections are in excess of the model predictions.
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