Deep inelastic scattering and its diffractive component, $ep to e^{prime}gamma^* p to e^{prime}XN$, have been studied at HERA with the ZEUS detector using an integrated luminosity of 52.4 pb$^{-1}$. The $M_X$ method has been used to extract the diffr
active contribution. A wide range in the centre-of-mass energy $W$ (37 -- 245 GeV), photon virtuality $Q^2$ (20 -- 450 GeV$^2$) and mass $M_X$ (0.28 -- 35 GeV) is covered. The diffractive cross section for $2 < M_X < 15$ GeV rises strongly with $W$, the rise becoming steeper as $Q^2$ increases. The data are also presented in terms of the diffractive structure function, $F^{rm D(3)}_2$, of the proton. For fixed $Q^2$ and fixed $M_X$, $xpom F^{rm D(3)}_2$ shows a strong rise as $xpom to 0$, where $xpom$ is the fraction of the proton momentum carried by the Pomeron. For Bjorken-$x < 1 cdot 10^{-3}$, $xpom F^{rm D(3)}_2$ shows positive $log Q^2$ scaling violations, while for $x ge 5 cdot 10^{-3}$ negative scaling violations are observed. The diffractive structure function is compatible with being leading twist. The data show that Regge factorisation is broken.
In order to extend the tracking acceptance, to improve the primary and secondary vertex reconstruction and thus enhancing the tagging capabilities for short lived particles, the ZEUS experiment at the HERA Collider at DESY installed a silicon strip v
ertex detector. The barrel part of the detector is a 63 cm long cylinder with silicon sensors arranged around an elliptical beampipe. The forward part consists of four circular shaped disks. In total just over 200k channels are read out using $2.9 {rm m^2}$ of silicon. In this report a detailed overview of the design and construction of the detector is given and the performance of the completed system is reviewed.
