Quark-Antiquark-Gluon Jets in DIS Diffractive Dissociation

We study the diffractive production of $q\bar{q}g$ jets with large transverse momenta in the region of large diffractive masses (small $\beta$). Cross sections for transverse and longitudinal photons are obtained in the leading log 1/x_{\fP} and log $1/\beta$ approximation, keeping all powers in log $k_t^2/Q^2$. We perform a numerical study and illustrate the angular distribution of the three jets. We also estimate the integrated diffractive three jet cross section and compare with the dijet cross section obtained before.Comment: 28 pages (Latex), 20 figures (Postscript

Predicting F2D(3) from the dipole cross-section

We employ a parameterisation of the proton dipole cross section previously extracted from electroproduction and photoproduction data to predict the diffractive structure function F2D(3)(Q^2, beta, xpom). Comparison with HERA H1 data yields good agreement.Comment: 5 pages,4 figures, Latex2e, uses espcrc1.sty. Presented at "Hadron 99" Beijing, August 1999. Reference added, erroneous citation correcte

Simultaneous QCD analysis of diffractive and inclusive DIS data

We perform a NLO QCD analysis of deep-inelastic scattering data, in which we account for absorptive corrections. These corrections are determined from a simultaneous analysis of diffractive deep-inelastic data. The absorptive effects are found to enhance the size of the gluon distribution at small x, such that a negative input gluon distribution at Q^2 = 1 GeV^2 is no longer required. We discuss the problem that the gluon distribution is valence-like at low scales, whereas the sea quark distribution grows with decreasing x. Our study hints at the possible importance of power corrections for Q^2 \simeq 1--2 GeV^2.Comment: 11 pages, 3 figures. Version published as a Rapid Communication in Phys. Rev.

Theoretical review of diffractive phenomena

We review QCD based descriptions of diffractive deep inelastic scattering emphasising the role of models with parton saturation. These models provide natural explanation of such experimentally observed facts as the constant ratio of the diffractive and total cross sections as a function of the Bjorken variable, and Regge factorization of diffractive parton distributions. The Ingelman-Schlein model and the soft color interaction model are also presented.Comment: plenary presentation at the Baryon04, 25-29 October 2004, Palaiseau, Franc

Das Genfer Modell zur Diskursanalyse - Möglichkeiten und Grenzen seiner Anwendung in der Exegese des Neuen Testaments = The Geneva model of discourse analysis and its application to New Testament exegesis: potential and limitations

Summaries in German and EnglishThe Geneva model of discourse analysis is a linguistic tool developed by Eddy Roulet and his team in Geneva. It was first presented in its modular approach in 1999. This dissertation examines whether the Geneva model can be applied to New Testament texts and whether this application yields results for exegesis. I first explain the model with its five basic modules and twelve organization forms, giving examples from German texts as well as simple New Testament examples. Then I apply the model to two New Testament texts (Rom 6:1,11 and John 8:31,42), summarizing the results in relation to exegesis at the end of each analysis. In the final chapter I discuss which parts of the Geneva model should generally be applied to New Testament exegesis, explaining its potential and its limitations and suggesting some areas in which the Geneva model could be complemented by other approaches.Das Genfer Modell ist ein von Eddy Roulet und seinem Team in Genf entwickelter linguistischer Ansatz zur Diskursanalyse. Er wurde 1999 erstmalig in seiner modularen Auspragung vorgestellt. In der vorliegenden Arbeit wird untersucht, ob dieses Modell auf neutestamentliche Texte angewendet werden kann und ob diese Anwendung einen Ertrag fur die Exegese bringt. Ich erlautere dazu das Modell mit seinen funf Grundmodulen und zwolf Modulverbindungen zunachst an deutschen und einfachen neutestamentlichen Beispielen. Sodann wende ich das Modell auf zwei neutestamentliche Texte an (Rom 6:1-11 und Joh 8:31-42). Am Ende jeder Anwendung fasse ich die Ergebnisse fur die Exegese dieser Texte zusammen. Im Schlusskapitel schliesslich erortere ich, welche Teile des Modells in der Exegese mit Gewinn eingesetzt werden konnen, wo Nutzen und Grenzen seiner Anwendung liegen und in welchen Bereichen das Modell durch andere Ansatze sinnvoll erganzt werden kann.New TestamentM. Th. (New Testament

The colour dipole approach to small-x processes

We explain why it is possible to formulate a wide variety of high energy (small-x) photon-proton processes in terms of a universal dipole cross section and compare and contrast various parameterizations of this function that exist in the literature.Comment: 6 pages, latex, 2 figures. Contribution to Durham Collider Workshop (Sept 99) proceeding

A QCD analysis of diffractive deep-inelastic scattering data

We perform a novel type of analysis of diffractive deep-inelastic scattering data, in which the input parton distributions of the Pomeron are parameterised using the perturbative QCD expressions. In particular, we treat individually the components of the Pomeron of different size. We are able to describe simultaneously both the recent ZEUS and H1 diffractive data. In addition to the usual two-gluon model for the perturbative Pomeron, we allow for the possibility that it may be made from two sea quarks.Comment: 13 pages, 5 figures. Version published in Eur. Phys. J.

High-p⊥p_\perp Jets in Diffractive Electroproduction

The diffractive production of high-$p_{\perp}$ jets in deep-inelastic scattering is studied in the semiclassical approach. The $p_{\perp}$-spectra of $q {\bar q}$ and $q {\bar q} g$ diffractive final states are found to be qualitatively different. For $q {\bar q}$ final states, which are produced by `hard' colour-singlet exchange, the $p_{\perp}$-spectrum is much softer than for $q {\bar q} g$ final states, where the colour neutralization is `soft'. Furthermore, the two different final states can be clearly distinguished by their diffractive mass distributions.Comment: 9 pages, latex, 5 figure