This thesis is made up of two parts. Part A - describes the construction of a scintillation counter and its operation, as an instrument for use in medical research. Part B - is a study of the stopping of mesons in various absorbers as a preliminary to the investigation of the meson decay process. / Thesis / Master of Science (MS)

No description available.

The purpose of this study was to investigate some theoretical approaches to the scattering of positive k-mesons by nucleons in an attempt to explain the experimental data. In this work the problem has been investigated by the technique of the weak coupling approximation.

Exotic mesons are mesons that cannot be described as a quark-antiquark pair. The number of exotic mesons has been growing every year in the charm sector and the theoretical understanding of them is often conflicted amongst the community. Some possible explanations include hybrid mesons where the quark-antiquark pair is coupled to a gluonic excitation, compact tetraquarks where four quarks are bound into a localised state and molecules which consist of pairs of extended mesons. To study exotic mesons from first principles, lattice QCD provides the framework to perform spectroscopy calculations numerically. I will give a review and describe the relevant techniques used in this thesis. After doing so, I will calculate masses of charmonium with angular momentum up to four. The results show QCD permits states with exotic quantum numbers that are not accessible by a quark-antiquark pair. I will identify states that are consistent with the quark-antiquark picture and then show that the remaining states in the extracted spectra can be interpreted to be the lightest and first excited hybrid meson supermultiplet. Whilst the mass is one quantity that can be computed, hadron spectroscopy is also concerned with the calculation of the unstable properties of resonances which can decay into meson-meson states. These meson-meson states have four quarks and could also mix with tetraquarks. I will describe how to correctly extract the energies of four quark states within lattice QCD by reviewing operators resembling meson-mesons and then constructing a general class of operators resembling tetraquarks. I will then calculate a variety of spectra in the isospin-1 hidden charm sector and the doubly charmed sector. No evidence of a bound state or narrow resonance is found in these channels. Having described how to include multi-meson states in lattice QCD, I will describe how to relate the lattice QCD spectrum to the scattering amplitudes and perform a calculation of elastic $DK$ scattering amplitudes which is relevant for the exotic $D_{s0}(2317)$. By analytically continuing the scattering amplitudes into the complex plane, I find a bound state pole near threshold which is in good agreement with what is found experimentally.

No description available.

Thesis (Ph. D.)--University of Chicago, Dept. of Physics, August 1997. / Includes bibliographical references. Also available on the Internet.

Ball State University LibrariesLibrary services and resources for knowledge buildingMasters ThesesThere is no abstract available for this thesis.

Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (p. 120-123).

The document describes a search for the rare decay B¯ → K¯vv̄ in a data set of about 230 millions of BB̄ pairs recorded by the BABAR detector at the PEP-II B Factory, via the process e⁺e⁻ → ϒ(4S) → BB̄. The method used selects events in which the B+ meson is fully reconstructed, and looks for a K¯ in the rest of the event. This is accomplished by applying kinematical and topological restrictions that select B¯ → K¯vv̄ events with the largest possible efficiency, while rejecting a maximum amount of background events. The number of background events is estimated from data and from simulated events, while the value of the selection efficiency relies solely on the simulation of B¯ → K¯vv̄ decays in the BABAR detector. These two numbers are required in order to set an upper limit on the branching ratio. We analyze a subset of the data sample and provide an interpretation of the result.

We study the hadronic phase of Quantum Chromodynamics within a formalism that uses strongly interacting resonances in the Regge theory approach. Our aim is to investigate the properties of the medium created in a relativistic nucleus-nucleus collision, using the electromagnetic decays of vector mesons as probe. To do so, we first layout the foundations of Regge theory, which is then used to calculate the in-medium properties of vector mesons. This methodology will be used to calculate for the first time the properties of the &phis; meson in a hadronic medium. The properties are contained within the imaginary part of the propagator (IMPP). Since it is related to electromagnetic decay via vector meson dominance, the IMPP is a probe of strongly interacting hadron gas created in the collision.