Deutsche Übersetzung des Titels: Exklusive Pomeron- und Odderon induzierte omega- und f2 Photoproduktion bei HERA

Vorschau

PDF, Englisch Download (8MB) | Nutzungsbedingungen

Übersetzung des Abstracts (Englisch)

The topics of this thesis are the analyses of exclusive photoproduction of $omega$- and $f_{2}$-mesons at mean $gp$ centre of mass energies of $langle Wangleapprox 200$ GeV at HERA. The former process is thought to be induced by photon-Pomeron interactions, and its cross section is measured to be $sigma(gpoomega p)=(1.3 pm 0.2(ext{stat}) pm 0.2(ext{syst})),muext{b}$, where the decay $omegaopigao3gamma$ is used to analyse the events. The diffractive slope $b$ describing the exponential fall of $ds/d|t|proptoexp(-b|t|)$ is measured by analysing the acceptance corrected differential distribution $d N/d|t|$. The value found for this parameter amounts to $b=(10.7pm 1.1(ext{stat})pm 2.0(ext{syst})),ext{GeV}^{-2}$. The corrected differential cross section $ds/d|t|$ is also found to be in accordance with the prediction of the Stochastic Vacuum Model for $ ho^{0}$-photoproduction scaled by a factor of $2/9$. The decay angular distributions $d N/dcosvartheta^{*}$ and $d N/dvarphi^{*}$ are found to be compatible with $s$-channel helicity conservation. The predictions of the Stochastic Vacuum Model for Odderon induced $f_{2}$-photoproduction of $21$ nb cannot be confirmed, but a $95$ confidence level upper limit on the cross section of $sigma(gpo f_{2}X)<12.4,ext{nb}$ is given. The contributions of the $f_{2}$ are looked for in the $pipi$ mass spectrum, where the $f_{2}$ is thought to contribute via its decay $f_{2}opipio4gamma$.