I present a series of calculations of the spectrum of low-lying hadron states using the formalism of lattice QCD. I discuss the approach taken by the UKQCD Collaboration in the simulation of QCD on the Grand Challenge supercomputer at Edinburgh, and the use of an improved action to reduce the discretisation errors of the computer model. I describe the techniques used in calculating hadron masses and decay constants from first principles and discuss the implementation of a spectrum-analysis program on the massively-parallel Grand Challenge machine. I introduce a new method of smearing hadron operators to improve their signals in simulations and describe the development and implementation of the Jacobi smearing algorithm. I present the results of UKQCD's light hadron spectrum calculations, including a new method of analysing <I>SU</I>(3) flavour symmetry breaking for hadrons composed of non-degenerate quarks. I discuss the calculation of the masses of hadrons composed of <I>u, d </I>and <I>s </I>quarks and present mass estimates for the <I>a</I><SUB>o</SUB>, <I>a</I><SUB>1</SUB>, <I>b<SUB>1</SUB></I>, <I>K</I>*, φ and η<SUB>s</SUB> mesons and the nucleon, , Σ, Δ,(<SUP>3</SUP>/<SUB>2</SUB>), Ω, Δ(<SUP>1</SUP>/<SUB>2</SUB>), <I>N </I>and Δ(<SUP>3</SUP>/<SUB>2</SUB>) baryons. Finally, I extend the ideas of combining degenerate and non-degenerate datasets to include calculations of mesons composed of one heavy and one light quark. I indicate how the quark mass dependence of the pseudoscalar and vector mesons may be described by a single function for the regime 0 ≤ <I>m</I><SUB>quark</SUB> ≤ <I>m</I><SUB>charm</SUB>. Using this method, I present mass estimates for the <I>D, D*, D<SUB>s</SUB></I>, <I>D*</I><SUB>s</SUB>, η<SUB>c</SUB> and <I>J</I>/ψ mesons.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:641399 |
| Date | January 1993 |
| Creators | Baxter, Robert M. |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14947 |
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