Universiẗat, Diss., 2003--Bonn.

Universiẗat, Diss., 2004--Münster (Westfalen).

University, Diss., 2004--Bonn.

University, Diss., 2005--München.

Techn. Hochsch., Diss., 2005--Aachen.

University, Diss., 2005--Frankfurt (Main). / Zsfassung in dt. Sprache.

Meson spectroscopy aims to study the masses and decay processes of mesons to better understand the mechanics of Quantum Chromo Dynamics in the strong coupling (non peturbative) regime. The Edinburgh group are spokespersons on a major new proposal at the Thomas Jefferson National Laboratory called MesonEx. This experiment will make use of the newly upgraded 12 GeV electron beam and detector systems to produce and measure the properties of mesons of interest for study. Edinburgh also leads the development of a fast timing Hodoscope, part of the new Forward Tagger detector system that will be essential to the success of this experiment. The primary focus of this thesis is the development process of the Foward Tagger Hodoscope, from its inception up to its installation at Jefferson Lab. The second part of the document will discuss the first measurement of the γp → ωππp decay channel, with data from the g11a run of the CLAS (CEBAF Large Acceptance Spectrometer) in Hall B of Jefferson Lab. The analysis presents evidence for resonant contributions to the dataset decaying directly to ωππ, via b1(1235)π or via ωρ. These include a2(1320), π1(1600), ω3(1670) and π2(1670).

A Partial Waves Analysis (PWA) of gamma p to Delta++ X to p pi+ pi- (eta) data taken with the CLAS detector at Jefferson Lab is presented in this work. This reaction is of interest because the Delta++ restricts the isospin of the possible X states, leaving the PWA with a smaller combination of partial waves, making it ideal to look for exotic mesons. It was proposed by Isgur and Paton that photoproduction is a plausible source for the Jpc=1-+ state through flux tube excitation. The pi1(1400) is such a state that has been produced with the use of hadron production but it has yet to be seen in photoproduction. A mass independent amplitude analysis of this channel was performed, followed by a mass dependent fit to extract the resonance parameters. The procedure used an event-based maximum likelihood method to maintain all correlations in the kinematics. The intensity and phase motion is mapped out for the contributing signals without requiring assumptions about the underlying processes. The strength of the PWA is in the analysis of the phase motion, which for resonance behavior is well defined. In the data presented, the eta pi- invariant mass spectrum shows contributions from the a0(980) and a2(1320) partial waves. No pi1 was observed under a clear a2 signal after the angular distributions of the decay products were analyzed using an amplitude analysis. In addition, this dissertation discusses trends in the data, along with the implemented techniques.

No description available.

The three main parts of this thesis demonstrate our current understanding of certain physics but mostly go beyond our understanding and present novel approaches, both technically and physically. The first part concentrates on the scalar mesons and presents search methodology to enable a better understanding of their existence and structures. The second part discusses one step further on beyond the standard model physics searches. Emphasis is given to discriminating factors between the MSSM and the U(1)' gauge extended models. The last part discusses a specific readout problem in calorimetry together with its solution and presents the digital hadron calorimetry, which will be an essential part of calorimeter systems of future colliders.