University, Diss., 2003--Heidelberg.

The two-particle correlation function is measured for neutral current DIS events with 5 < Q2 < 100 GeV2 with data taken by the H1 detector at HERA with -vFs = 300 GeV during the 1994 run period corresponding to an integrated luminosity of 1.3 pb-1. The diffractive and non-diffractive selections of the data are analysed separately, and both exhibit an enhanced correlation for small 4-momentum difference for like-sign pairs as expected from Bose-Einstein interference in the production amplitudes for identical boson pairs. Fits using a Gaussian parametrisation of the enhancement yield no statistically significant difference between the diffractive and non-diffractive samples. The non-diffractive data sample is further separately analysed in three bins of each of the kinematic variables x, Q2, and W as well as mean particle density, (dn/dry*), in the hadronic centre of mass frame. Of these a strong evolution of the Gaussian fit parameters is observed with increasing particle density only. The non-diffractive data are also compared to three fit parameterisations: Gaussian, exponential, and power-law. The most favourable X2 is obtained for the exponential fit, though the power-law attains a similarly successful description of the data in the region of low 4-momentum difference.

Heidelberg, Univ., Diplomarbeit, 1996.

Heidelberg, Univ., Diplomarb., 1999.

Heidelberg, Univ., Diplomarb., 1997.

Universiẗat, Diss., 1999--Mannheim.

Universiẗat, Diss., 2001--Mannheim.

No description available.

Photoproduction has been used at colliders for decades in order to study hadronic properties of matter. The energy and luminosity of recent and future colliders allow probing also the electroweak sector through photon-photon and photon-proton interactions. At the HERA electron-proton collider, studies of the W boson production provide a stringent test of the Standard Model. At the LHC, photoproduction has to be separated from the overwhelming background of partonic interactions. A powerful ‘tagging’ technique can be introduced by adding special detectors placed far from the interaction point to detect forward scattered protons, usually present in photon-mediated processes. The HECTOR software package was written in order to provide accurate simulation of forward protons trajectories in the LHC beam-lines. These tools have been used in order to study the photoproduction of top quarks via flavor-changing neutral currents. This process is practically absent in the Standard Model, while it appears in some of its extensions. Detection of such a process would thus be an evidence for the existence of physics beyond the Standard Model.

Heidelberg, Univ., Diss., 2007.